There are lots of ways. If you're a new cook, I'd recommend broiling them.
Sprinkle on both sides with salt, pepper, and any one herb you have on hand (I like tarragon, thyme is also classic, but really you can use just about anything with chicken.)
Line a cookie sheet with foil for easy cleanup and put the legs on top, under the broiler. Your oven should have a broil setting, which is normally maximum heat. In broiling, the heating element is on the top of the oven, so have the oven rack close to the broiler. (Some ovens have a separate broiling compartment, so check where the heat is coming from.)
Broil for 10 minutes, then turn the legs over and broil 10 more minutes.
This is not the most even way to cook legs, but it's simple and should taste fine.
It's not so hard to bake or grill, either but avoid frying: fried chicken is an art unto itself and unless you know what you're doing with frying you can make a huge mess and/or start a big fire.