I'll jump in!
How do I deal hits against already broken unit. I shoot once against enemy unit and IFT says it is flipped on its broken side. Then another my unit shoots same unit. What happens ? (if it gets hitted)
If your first attack broked the enemy unit (it fliped it) and a second attack gives you a result in the IFT, you have to do as the result says (NMC, #MC, KIA) taking into account that the Morale of the broken unit is on the side that it is now facing (the broken side).
If a broken unit fails a MC, then it is casualty reduced (a squad turns into a HS and a HS disappears.
Is there situations where Residual Firepower counter is left on hex with unit? Or is RFP counters always left "behind".
Moving unit in H4 gets shooted by enemy but nothing happens so unit is moving to H5 and gets heavily hitted. I place RFP counter on H4 but do I place RFP counter on H5 too ?
Residual FP is left on the hex you fired, if the unit stays there, it would stay under the residual FP, but if it moves, the residual FP stays in the same hex.
e.g. A unit moves into hex A1 and it is attacked with 6 FP so you leave a 2 (half of IFT column, rounded down to the nearest column) residual FP marker in A1.
The unit moves now to A2 were it is attacked again with 3FP so you leave a 1 residual FP marker in A2. The unit stops in A2.
A second unit moves now to A1. Receives the residual FP attack and then it stops (or it continues its movement).
I hope I have helped you