Steps

Installation - Linux

1. Ensure your system is up to date
2. apt-get update && apt-get upgrade -y
3. Go to Plex site and download the lastest
4. https://www.plex.tv/media-server-downloads/
5. wget __FILE_LINK__
6. sudo dpkg -i plexmediaserver__VERSION__.deb
7. rm -fr plexmediaserver__VERSION__.deb
8. Enable and start it
9. sudo systemctl enable plexmediaserver.service
10. sudo systemctl start plexmediaserver.service
11. Open a Tunnel to set it (Putty for windows)
12. Go on SSH -> Tunnels
13. source port : 8888
14. destination: __HOST_IP__:32400
15. Click on "Add"
16. Go on Session
17. host: __HOST_IP__
18. port: 4747
19. Click on "Open"
20. user: root
21. password: __YOUR_PASSWORD__
22. Open in browser : http://localhost:8888/web

Installation - Synology Nas

1. Go in your internet browser and type: https://www.plex.tv/media-server-downloads/
2. /!\ Depends on your CPU, but normally you will select "Synology" -> "64 bits"!
3. Go to "Package Center" -> "Manual install" Plex 64 bits
4. Buy (if you don't have it) Plex Pass to be able to use the transcoding option
5. https://www.plex.tv/plex-pass

Setting up

1. Connect to your Plex Account
2. Setup Plex
3. Define the server name (when asked)
4. > Create needed directories, like :
5. mkdir -p "/home/Applications"
6. mkdir -p "/home/Books"
7. mkdir -p "/home/Movies"
8. mkdir -p "/home/Music"
9. mkdir -p "/home/Other"
10. mkdir -p "/home/Other Videos"
11. mkdir -p "/home/Photos
12. mkdir -p "/home/TVShows"
13. Click on "Add Library" and fill all fields (name, path, etc.)
14. Settings
15. Online Media Sources -> Disabled all
16. General -> Uncheck "Send crash reports to Plex"
17. General -> Uncheck "Push Notifications"
18. General -> Uncheck "Enable Plex Media Server debug logging"
19. General -> Uncheck "Enable Plex Media Server verbose logging"
20. Remote Access -> "Internet upload speed" -> Do a speedtest.net and write upload value (c.f.: 220 Mo)
21. Remote Access -> "Limit remote stream bitrate" -> Original (No limit)
22. Agents -> __YOUR_CHOICE__
23. Library -> Check "Scan my library automatically"
24. Library -> Check "Run a partial scan when changes are detected"
25. Library -> Check "Include music libraries in automatic updates"
26. Library -> Check "Scan my library periodically"
27. Library -> "Library scan interval" -> "daily"
28. Library -> Check "Empty trash automatically after every scan"
29. Library -> Uncheck "Allow media deletion"
30. Library -> "Weeks to consider for Continue Watching" -> "16"
31. Library -> "Maximum number of Continue Watching items which will appear" -> "20"
32. Library -> Check "Include season premieres in Continue Watching"
33. Library -> "Video played threshold" -> "90%"
34. Library -> "Video play completion behaviour" -> "earliest between thershold percent and first credits marker"
35. Library -> Uncheck "Enable smart shuffling on artists and smart music playlists"
36. Library -> "Group albums by type" -> "enabled"
37. Library -> Uncheck "Enable iTunes plugin"
38. Library -> Check "Run scanner tasks at a lower priority"
39. Library -> "Marker source" -> "both, try online first"
40. Library -> "Generate video preview thumbnails" -> "never"
41. Library -> "Generate intro video markers" -> "as a scheduled task when media is added"
42. Library -> "Generate credits video markers" -> "as a scheduled task when media is added"
43. Library -> "Generate chapter thumbnails" -> "never"
44. Library -> "Analyze audio tracks for loudness" -> "never"
45. Library -> "Analyze audio tracks for sonic features" -> "never"
46. Library -> "Location visibility" -> "admin only"
47. Library -> "Database Cache Size (MB)" -> "60"
48. Network -> Check "Enable server support for IPv6"
49. Network -> "Secure connections" -> "Preferred"
50. Network -> Uncheck "Enable local network discovery (GDM)"
51. Network -> "Remote streams allowed per user" -> 4
52. Transcoder -> "Transcoder quality" -> "Automatic"
53. Transcoder -> "Background transcoding x264 preset" -> "Very fast"
54. Transcoder -> Check "Enable HDR tone mapping"
55. Transcoder -> Uncheck "Disable video stream transcoding"
56. Transcoder -> Check "Use hardware acceleration when available" (Plex Pass)
57. Transcoder -> Check "Use hardware-accelerated video encoding" (Plex Pass)
58. Transcoder -> "Hardware transcoding device" -> "Auto"
59. Transcoder -> "Maximum simultaneous video transcode" -> "Unlimited"
60. Languages -> Check "Automatically select audio and subtitle tracks"
61. Languages -> "Prefer audio tracks in" -> __YOUR_CHOICE__
62. Languages -> "Subtitle mode" -> "Shown with foreign audio"
63. Languages -> "Prefer subtitles in" -> __YOUR_CHOICE__
64. DLNA -> Uncheck "Enable the DLNA server"
65. Scheduled Tasks -> "Time at which tasks start to run" -> "2 am"
66. Scheduled Tasks -> "Time at which tasks stop running" -> "5 am"
67. Scheduled Tasks -> Check all
68. Extras -> "Choose Cinema Trailers from" -> "Only unwatched movies"
69. Extras -> Check "Include Cinema Trailers from movies in my library"
70. Extras -> Uncheck "Include Cinema Trailers from new and upcoming movies in theaters" (Plex Pass)
71. Extras -> Uncheck "Include Cinema Trailers from new and upcoming movies on Blu-ray" (Plex Pass)
72. Extras -> Check "Always include English language Cinema Trailers for trailers of movies not in my library"
73. Player settings - Plex Web
74. General -> "Language" -> __YOUR_CHOICE__
75. General -> Uncheck "Automatically Sign In"
76. General -> Check "Remember selected tab"
77. General -> Uncheck "Play Theme Music"
78. General -> "Time Format" -> "24 Hour"
79. Quality -> Uncheck "Automatically adjust quality (Beta)"
80. Quality -> "Video quality"-> "Maximum" (so use original stream receive from the server)
81. /!\ But if you have trouble, try the speed just before, and again until have no lags on device!
82. Quality -> Check "Play smaller videos at original quality"
83. Quality -> Check "Use recommended settings"
84. Debug -> "Debug Level" -> "Disabled"
85. Debug -> Check "Direct Play"
86. Debug -> Check "Direct Stream"
87. Debug -> Uncheck "Use alternate streaming protocol for video playback"
88. Player -> __YOUR_CHOICE__ (c.f.: default is nice)
89. Player settings - Plex Android
90. Experience -> Check "Remember selected tab"
91. Experience -> Uncheck "Play Theme Music"
92. Sync -> Check "Use mobile data"
93. Quality -> Uncheck "Automatically adjust quality (Beta)"
94. Quality -> Uncheck "Limit mobile data"
95. Quality -> "Remote streaming" -> "Maximum" (so use original stream receive from the server)
96. Advanced -> "Name" -> __YOUR_CHOICE__
97. Confidentiality -> Uncheck "Send crash reports"
98. Player -> Check "Prefere synchronized media"
99. Player -> "Maximum level H264" -> 6.0 (Recommended)
100. Upgrade Plex
101. > Simply redo the "Installation" depends on your system
102. Backup (and Restore)
103. Copy (Replace) all following directories and files:
104. /lib/systemd/system/plexmediaserver.service
105. /var/lib/plexmediaserver/Library/Application Support/Plex Media Server
106. Problems (on readers)
107. If your player (Windows, Android, etc.) can no longer play videos, make sure you have disabled the new video player which is not supported everywhere
108. Settings -> Advanced -> Activate new video player: Off