Potty training advice please

My son is getting frustrated with his diaper, every time he pees, even if it's just a little bit, he immediately wants his diaper off. I've been trying to introduce the potty but he doesn't get it. He'll sit there until I put his diaper back on then he'll pee and immediately want changed. I've tried reading potty books and singing song, I'll take him into the bathroom with me so he can see how it's done. Dose anyone have any tips or tricks on this?