Black and white are both postitive, it doesn't matter what they go on, and the green (ground) goes on the bottom hole, just like a 120v receptacle.
when connecting to your breakers, just make sure teh white and black have the same size breaker.... then you're golden.

89 4Runner
3" BL, M/T locks, 33"bfg mt, bilstein, Kayline, tubebumper, toyotafiberglass panels
TBI: Elocker,3.4 w/ORS,b+b,S2Sstg2cams,arias pistons,P+P intake,TRDs/c,URDpullies+7th,downey headers,MAPECU2,WEGO WB, SupraMAF,walboro255,stg4clutch, EPaOo2 sim