Photoshop is a great tool for thumbnails, but wow is it complicated. If you are looking for the easy and free way to get good looking thumbnails then check out this tutorial on how I create my own thumbnails, in ten minutes or less using Canva. You don't need to pay anything to get started, but I have been using the pro version for years and am really happy with the resources they provide.
Affiliate link to canvas pro (it doesn't cost anymore to you but helps support me as a creator) https://partner.canva.com/c/3836060/6...