At the bottom of the radiator on the driver's side, there is a
drain valve which allows you to drain the fluid. It looks like a
wingnut, and there is a small spigot just underneath the wingnut.
Attach a small piece of hose to that spigot, and the fluid will
drain out of the hose and into a receptacle. If you want, you can
keep turning the wingnut and it will completely come out, making
the draining process much faster.