Just pull the lower radiator hose. It’s a big messy gush at first, but the petcocks aren’t worth the trouble.
What I would also suggest is that you go pick up a basic repair manual. If you really want to get into working on this car, get an actual factory service manual. However, do note that these are written toward people who already know things about cars and have lots of tools that you probably don’t. If you just want an easy, basic manual for the basic DIY stuff a Haynes manual will suffice and is available at most any auto parts store. Chapter 1 normally contains guides for all of the basic maintenance stuff. The Haynes manuals are NOT very good if you see yourself ever wanting to really get into doing your own repairs. But for basic driveway stuff it’ll do.