Installed new starter and it still wont turn over.

Installed new starter, and battery. Starter isn't
engaging... Pulled one link fuse today and will
replace it later tonight (casing to wire was stiff,
crumbling and old). Not sure if the link fuse to the
starter but will change replace it anyway. From the
battery to the starter what issues could arise that
would cause my starter to not engaged when key
is turned? Also I drove this car one time and it
started right up.