When you pulled the first two screws with the screens how much oil came out? It should of been only a couple of teaspoons, the one without the screen should of release all of the oil. Don't forget, start up the engine first, it doesn't have to run long, shut it off then pull all of the drain screws. Like I said before measure all of the oil that comes out (if you liked what was on the dip stick after the little warm up) replace with the like amount. If you've got oil all over the engine you've put in too much and it's pumping it into the oil breather which goes to the air filter,(follow the hose from the crankcase). Open the air filter box with the key, if you have oil in there you have over filled the engine. No big deal, just messy, drain some out (which is impossible to do with out the mess), did you check the dip stick after the oil change? You'll get the hang of it.
Don