A battle management system manages a battle.
You have tanks and lots of other vehicles in a battle zone and you also have assets whose purpose is to locate and identify targets.
Say there is a unit of 4 T-90AMs in a village and there is a Russian UAV overhead with a birds eye view of the surrounding area. Any enemy targets that UAV might detect will be transmitted to HQ via the operator of the UAV and because the operator of the UAV is connected to the network he knows the 4 T-90AMs are in that village so when 2 enemy tanks are spotted coming up the road 30km away the UAV unit will ID the threat vehicles and pass the info up to HQ who will verify using other platforms nearby like JSTARs like aircraft or any recon units, and once the new targets are verified they become part of the system map... so the map the T-90AMs are looking at will suddenly have two enemy tanks appear in their last known position. Their presence will likely result in a request for the UAV that spotted them to monitor their position and keep it updated on the live map.
The tanks might have a hill between them and the target but they are now aware of their presence.
Any other enemy activity noticed by the T-90AM tanks or Mi-28N helicopters or satellites passing over, or Ka-52 recon helos is also added to the map.
It is not just a map however, it can be used to pass orders down to individual vehicles and soldiers... if instead of 2 enemy tanks coming it was 200 the 4 T-90AMs might be commanded to position themselves where they can see the targets at very long range to allow them to call in Artillery strikes or air strikes.
The new 7km range missiles might be SALH missiles instead of laser beam riding so when the enemy tanks get within range the four tanks could fire missiles over the hill and the UAV could mark the target tanks with a coded laser so the enemy tanks would not even see the tanks firing the missiles.
Etc etc.
YeosuTK is a C4IR system.