I taught myself how to write POP because I have some basic knowledge of painting and I thought it was quite simple. You can buy several different copybooks now on the market and take them home to practice and master the writing skills. It's not difficult. Don't go to those crash courses. They're all scams. You won't learn anything at all. It depends on your understanding. I wish you can draw good works as soon as possible! More practice and more copying will definitely be beneficial!!