Your walking foot is for doing mostly straight line quilting. You can do gentle curves too. You usually have to buy it for your certain machine as there are several. You can use your regular straight stitching foot but you need to keep a good eye on the quilt sandwich as it tends to creep.
The Free motion or darning foot lets you sew in any direction and you can do any pattern. Go watch Leah Day tutorials for good tips.
Start with a simple tablerunner and just quilt straight lines down the length about 4 inches apart. This will give you a feel for the process. If you have a darning/hopping/FM foot (lower your feed dogs) put a few sqiggle patterns in between the straight lines. Ta Da, you're a machine quilter!