I use CorelDraw myself. Mostly the Paint program. I have never come close to being a master of it. I have tried Photoshop but find Corel easier to use thought there are more how to’s for Photoshop. They can translate over to Corel.
GIMP is free and there are many video help how to’s to look at. Many at youtube.
GIMP 2.8 Tutorial Part 1 - The Basics
https://www.youtube.com/watch?v=W88LB8clHrs
I used Corel years and years ago, and it was nice, but I’ve always stuck to Adobe since then.
And yes, I know how to use GIMP, but I prefer not to. It is not user friendly, and everything you want to do generally takes two or three steps where it would take only one in Adobe.