It's fairly visual: disconnect all the stuff connected to the old one, remove it, and install the new one. You will need four tall, safe jackstands and a transmission jack (see Hwrbor Freight for a less expensive one, or rent one.)

The new transmission should have the front seal renewed and the tailshaft bushing and seal replaced before it goes in. These are normal maintenance items and can be done very easily while it is out. When you get the old tranny out, replace the engine rear crank seal too.