A couple of questions:
- Are there lines of supply ?
There no lines of supply, but the supply system offers different rule sets to choose from.
In the detailed supply rules you need to use your resources on ammo and fuel thus leading to the choice between that and refitting the troops.
Also those costs vary, depending on the operation. Early stage costs of fuel for the Germans e.g. are significant lower than those in a battle like at Moscow '41 in the winter.
- What about the action system ? Is it one move and one attack per turn, or a full action point system ?
We have an action point system, it allows multiple moves per turn, but only one attack in it. There are recon units that have 4 action points and can scout in four steps into enemy territory as long as their movement points are not used up or they don't run out of fuel.
You can also move a unit, leave it, move another, and go back to the first and use up its action/movement points or attack at will. You are not bound to do everthing at once, you choose the order of actions.