1990 Chevy Corsica starter

Welcome to the forum, take the negative battery loose first. The positive battery cable should lead to the starter. On some makes and models, the oil filter and sending unit may be close to the back of starter, if that is the case, remove them, then when the starter mounting bolts are removed, you can back-out the starter from the flywheel housing. Don't forget about oil sending unit and filter if removed.