Installing multi-batterys

I want to install 2 more batterys in my truck to (1)run my air compressors and (1) to run my sound system. How do I go about this? What do I need to do? How do I wire it up. Is there any special things I need to buy to make it work? How do I wire it all into the altenator. ETC... I know nothing about doing this... so ANY help would be great.

Thanks