To find an anchor, first learn to consistently come to full draw with good back tension. You say you do that. Good! Because if you pick an anchor that forces you to short-draw, you may never learn to come to full draw.
After you have good alignment, begin to notice where your string hand ends up. There should be some part of your face, like your jawbone, that is immovable and you can touch with a thumb knuckle or finger. Maybe it will be your eyetooth; maybe not.
Some of us use Rick Welch's nose anchor, where we mount the feathers on our arrows such that the cock feather touches the tip of the nose at full draw, which makes a good draw check. Or, you can accomplish much the same thing by mounting the feathers such that the cock feather touches your upper lip or mustache.
Most good trad archers tend to use at least two anchors.