Kegels and edging aren’t supposed to cause any penis gains; they’re for training yourself to last longer and have harder erections.
Kegels are about learning to control and strengthen your Pubococcygeus and Bulbospongiosus muscles. These are the muscles involved, among other things, with you getting an erection and ejaculating. Strengthening the muscles will help you get and hold a harder erection, while learning to control the muscles will help you to hold back from ejaculating. You also use these muscles when you move your bowels, and in women they’re the vaginal muscles involved in orgasms and giving birth. So they aren’t just about getting you an erection.
Kegels are just you voluntarily contracting the muscles, which is primarily for strengthening them but will also help you learn to control them. Edging is an exercise for learning to control these muscles to prevent yourself from ejaculating. When edging, focus on what your muscles are doing down there as you feel the oncoming orgasm; you should feel them contracting in preparation for ejaculation, so when you back off try to get them to relax. The goal here is learning how to control these and preventing them from firing off when you don’t want them to. You should also pay attention to other muscles in your body as well, when you get close to ejaculating you tend to tense up your whole body. This is also an exercise in will power, since you have to actively deny your desire to go over the brink of the orgasm.
But don’t confuse these for penis enlargement exercises; that’s not what these are intended to do. If you’re looking for penis enlargement then those would be Jelqing exercises, stretching, pumping, or clamping.