Replacing a radiator is pretty much as straight forward as it would appear
to be.  Do be prepared though, after you're done, you may find yourself
wrestling with evacuating all of the air from the system.  Trapped air can
cause the water pump not to circulate the coolant properly, and it may tend
to want to overheat until you get all of the air out.  It will likely take
cycles of running it, topping off the coolant, shutting it down, topping off
the coolant, ad nauseum.  Squeezing the radiator hoses can sometimes help
move the air bubbles, sometimes not.

Take the opportunity though, to flush the system and put new coolant in.
You can flush it with just a garden hose and clear water.  Sometimes the
garden hose is useful in pushing the trapped air through the block and out
to atmosphere.