This problem will mostly occur on the 4th mission night call for the germans as this is also the first mission where you have to take command. you can get to around 2 objectives no problem but then you will start to have the problem that your men will run out of ammo. For this mission you have an armory not far from the motorpool it's best to go there as fast as you can. once you are there or anywhere else with some form of ammunition nearby you can start rearming your troops.

So far I only know that you have to select each soldier seperatly to rearm them. If you have selected a soldier press 6 and a list of actions for that soldier will show up as seen in the screenshot.

Simply scroll to the rearm option or order him to pick up another weapon.







To heal your units you can either select your medic and order him to heal your units (by pressing 6 you can select the healing option faster then searching for the wounded soldier) or you can order the wounded soldiers again individually and look for the option heal at vehicle or structure when one is nearby that can heal your units.

I hope this will solve some problems with completing missions.