looking for a little help on replacing a tensioner pulley on an 01' alero...directions?

use a impact on the bolt verses your bare hands and it spins off put the new one and tighten with the impact

is it easy to get at?

cant rember but at the very worst youll have to pull the side fender or radiator this is at the worst but its rather easy to do

Difficult area to get an impact into, maybe a 3/8 air ratchet, but an impact is not going to work.

that should work but no promises you may need a higher touqure ratchet