Entire books are written about this so a forum is not the best starting point, perhaps if you had specific questions we could better help. Your best bet is to go to youtube and find some computer animated videos. If you really are interested go buy a 1/4 scale clear plastic model (
1/4 Visible V-8 Engine by
Revell-Monogram) for about 50 bucks. These scale models are usually older outdated engines but are a great foundation to learn from. Also assembling the parts yourself really helps you to understand everything. I assembled mine in a day. First things first, google the terms ''4 stroke engine''.
Basically air is sucked into the engine through the air box and air intake, it then mixes with fuel, this mixture is sucked into the combustion chamber where it then get compressed, then a spark ignites it, it explodes and expands. This expansion causes a complex mechanical movement of parts which ultimately turn the wheels. After the explosion there is left over gas which is basically unusable and it get forced out through the exhaust manifold and muffler. I would really check out a book or that scale model .
FYI the scale models uses a hand crank to turn and you can see all the parts move. Its pretty good and only overlooks a few minor things, its about as good a starting point as you will find.