"how do i made amp ohm instead of 4"
What?
I think you're asking how to make the amp 2 ohm. If your 12's are already wired for 2 ohm, just connect the 2 leads to the bridged terminals on the amp. There will be 4 connections on the amp. One for each channel. Usually, the two outside terminals (one positive and one negative) are the bridge and it'll be noted with a line painted on the surface above the terminals. That's all you have to do.
If it is overheating, you should put cooling fans on it.