I'm not gonna teach you how to lead men into battle, just the abilities and general purpose of the Officer/SL role in the game and how to use it. LOTS of opinion in this video, if you don't like, I don't care.
https://www.youtube.com/watch?v=oNsReI5IKDc
A great example of garrisons winning a game. Pause after each build to see the map and where they're placed
0:00 Intro
0:27 Outposts and placement
2:16 Garrisons and placement
4:53 Combat Area explained
6:38 Garrison Separation Distance explained
9:59 Game Start explanation
10:52 Game Start Garrison placement
12:50 When the enemy takes a sector
13:25 Starting Garrison Philosophy
14:46 Placing Good Garrisons
16:58 Defensive Garrison ideas
20:34 How I think a good Defensive set-up looks
23:30 Thinking ahead with Garrisons
26:20 Friendly Garry lockout from enemies
30:15 Into to Map Marking
31:18 Who sees what Mark
33:16 Marking with allied pings
34:50 Why using VOIP is important when marking
35:46 Battlefield Awareness
37:20 Examples of Marking and how to read them
40:35 Conclusion