Hi LolYou will have two cables coming out of the inverter, one red and one black. The black goes direct to the negative terminal, the red to the positive. Mount the inverter in a ventilated area where the fan can do it's job of keeping the unit cool. If the unit came with croc clips I would suggest changing these to something more permanent.
What rating in watts does the inverter have, Lisa?
It's a 300W (now don't go and tell me it'll be no good).
Lisa