Kilakan
I'd really prefer have my dwarfs tantrum, then be slaughtered like pigs.
I really just need to know how the hell burrows work, how to get those idiots to train, how to schedule them properly, and the alert system.
This is all just from memory, and the wiki is blocked from here so some/all of this could be wrong... but here goes.
1. Assign dwarves to squads as appropriate
2. (Optional) Create a uniform; a good idea if everyone is going to be equipped the same.
3. Assign dwarves equipment; note that uniforms are
created under "uniforms", but they are
equipped under "equipment".
4. Set the squad's alert level to "Train/active". Alert levels basically determine what schedule they'll use, and you want them training.
5. (Optional) Customise the squad's schedule; by default, their order will be "Train: Min 10" for every month. This means that all dwarves will train at all times; you'll need to set the minimum number to something less than the size of the squad if you want them to be able to take breaks. Someone will need to confirm whether dwarves will actually starve themselves if this number is too high; I
think this was fixed.
6. IMPORTANT! Assign a barracks. You can do this from a bed, chest, weapon rack, or armor stand. Make sure each individual squad is set to (T)rain at the barracks.
If you've done all of this right, you should see them start doing group combat demonstrations / sparring. If not, check that their alert is set to Active/Train. If you see them doing individual combat drills, they're doing so in their free time and NOT set to train. You will also see their profession switch from civillan (Farmer, peasant e.t.c) to their military one (recruit, wrestler e.t.c) once everything is set up right.
Good luck!