help mid skirmish?

[yourgi952]

Hi all, I am having trouble, when I play a skirmish I start off ok but when I get to about mid game I don't really know what to do, I can win on easy easily enough but when it gets about mid game i don't know what units to make or if i should go infantry and tanks or just one, should I spread my units out and try to take all the zones or just go down the middle or side? I prefer infantry but i only use tanks because I have to to kill the enemy tanks, I guess I would like to know if there is a way to find out about the units in game like in multiplayer(like when you click the i button on their icon) so I can find out what the units are best used for but a way to do it in single so I dont just sit in someones match not doing anything or just any tips would be cool too, thanks