Just guessing, but might be worth a try: open the hood, go to the right side of the engine and try to locate blower motor housing. If not there, than you'll probably have to get underneath dashboard on the right side and start unscrewing a whole lot of plastic covers to get to it. You'll probably get better answer from someone who owns a classic, but i gave my best try.
raise hood, go to passenger side of motor, look right behind the air breather intake, against the firewall is a 3" wide by about 10" tall black
panel that has 2 skinny steel rods (their connected at the top) going straight up and down, pull at the top of the rods, it's actually a retaining
clip that keeps the little black panel on. slide/pull the panel out towards you and the filter comes out with the black panel, hold the filter and slide
the black panel off of it to the right. you buy a new filter, not the black panel, clip the new filter onto the black panel and slide it back into the filter
housing. pretty simple.