Wiring for dual batteries...help

[jott_06]

Ok this is actually for my daily driver sonoma but you guys talk more than the s-10 guys... i bought two new batteries and some battery cable and i plan to run dual batteries in the bed because the guy i got the truck from said the compressor for my bags draws to many amps and he's ruined a few batteries. Do i just connect the two batteries with the cable i bought by going positive to positive and negative to negative? That should keep it 12 volts correct? My regular battery is already mounted in the bed so i am just goint to replace it with the two i bought.