How to change an air filter on most cars and trucks

Air filter are often mounted on top or to the side of the engine.
The top mounted filters are usually a round ring filter you fit into a metal 'pan' shaped container positioned right on top of the engine. It will be fastened shut with either clips around the edge or a Wing nut in the centre of the lid. Release the clips or unscrew the wing nut and lift off the lid. The filter should lift out, drop in the new one, refit the lid and refit the clips or the wing nut.
The side mounted filters are often positioned over towards one of the inner fenders and can sometimes be more of a pain to change. They use a slab filter usually about the size of a large book.
Look for a big, wide plastic tube, (likely to be 2 to 3 inches wide), coming from the top of the engine over to a large black plastic box. This will be held closed with either screws or 'hook over' clips. The box will have a rib going all the way around the sides. This is where the fasteners will be. Check all four sides for fasteners ( I've missed screws or clips and wondered why the lid won't come off). You might need to wiggle the lid high enough to slide the filters in and out. Fit the new filter the same way up as the old one the refit the clips/screws.

right beside the engine (the engine is in the middle) in a black box usually over a wheel. The black box will have clips (3-4) that you need to unhook. lift the box apart (might have to use some strength) take the old filter out. its about an inch thick. clean out the bottom of the box out of some debris. install the new filter positioned like the old on. close the clips. if the clips connect then youve install it properly.

its usually on the top of the fire wall. in a big squre looking box with round plastic tubes coming out and hooking up 2 the motor. it usualy has fasteners 2 open the box. open the box air filter should be in theres

look on the fire wall on the drivers side in front of a big round thing with fluid and metal tubes coming from it. Its attached to the brake booster

Its located on the drivers side just behind the battery and in front of the strut tower, a black square box with a black round plastic tube going to it, remove the top cover and you will see the square air filter inside.