Timestamps below, but I recommend watching the entire video. The following is a complete guide to offmap artillery in Graviteam Tactics: Mius Front, covering both the operational map and tactical engagements.

0:00 Assigning offmap artillery to battlegroups
1:43 How much ammunition does my artillery have?
3:00 Using offmap artillery in engagements
SOME SUBCATEGORIES
4:08 Fixed orientation of the firing lane
5:08 Walking/Creeping barrage
7:59 Zeroing in
16:30 Accuracy/Dispersion changes
18:30 How do I know before the engagement if my artillery will be scheduled or oncall?
26:56 A few final notes on scheduled artillery