"Just says match up two pieces with wrong sides together and sew." With the batting between, right? That makes 3 pieces.
Some of my first quilts were rag quilts. They were soft and nice just using flannel. Some tips... flannels come in closer weave and looser weave and there is a world of difference! The looser isn't nearly as "friendly" as the closer; it becomes flat and bare after a bit.
AND buy a pair of spring loaded scissors! Mine are full size, but since I don't have to pull them apart after each clip (opening the blades) I only have to do half the work. My hands swelled up terribly (I have some arthritis) the first time I did the clipping for a quilt and my wonderful DH asked at the cutting desk if there were any scissors made for clipping edges of rag quilts! It not only is less painful, but it is sooo much faster!
Also, be sure to machine wash them several times to get rid of the loose threads. Nothing doesn't please a mommy more than seeing her child eat the edges of the quilts that come off so readily (or are already off due to use).