Buy and/or download the book: https://magpi.raspberrypi.com/books/essentials-c-v1
Start slowly, learn the basics, don't be lazy and experiment on your computer. This can be hard, you are not stupid, persevere and you will get it.
I recommend you do your learning in the morning, after a good night rest, in sessions that last just a couple of hours. Caffeine is not a replacement for a well slept night.
What you learn from the book is pretty much applicable on every Operating System and computer, not just the Raspberry pi.
Related Youtube videos: https://www.youtube.com/channel/UCLnErjcaZuhwHX6gjyTxrwA
Linux users, particularly those using the Raspberry pi, have all the tools they need pre-installed (the wonders of using a free operating system that happens to be far better than its commercial counterparts never ceases to amaze me...).
For Windows users I suggest you use Codeblocks (compiler and IDE/editor): http://www.codeblocks.org
Mac users will probably try to use Xcode, however, I think the IDE/editor is terrible for beginners. I would suggest you install Xcode, add the command line tools (part of the installation) and then use Sublime text : https://www.sublimetext.com to write and test your code. It's much better (even for seasoned coders).