The rear seal housing needs to come off, and the front plate if it is a diesel. I'm assuming the flywheel is already off, because it is bolted to the back of the crankshaft. If it's still on, you'll need to take it off to get the rear seal off.

Short of that, it should be a matter of taking the main caps off and dropping the crank down. It might be easier with the oil pump out of the way too. 

Don't drop it on your toes, and make sure the main caps stay in the right order. If they aren't already marked, make sure you can identify which one is #1 (front), through #4 (rear). It is very important to keep them in the same locations when you put the engine back together. Chances are they are already marked somehow.