My suggestion is for him to write "I have Manjaro installed, how do i update the system?" but Manjaro also includes an updater. "How I install on Linux Mint the GIMP program for photo editing?" these are examples. Since it is very diferent from Windows where you have to go to a website and download some installer, you do have to learn how to use Linux and ChatGPT or Perplexity will help him.

I don't recommend Linux Mint just because it is Ubuntu based and I don't like Ubuntu. I would rather install Debian and put XFCE4 than any Ubuntu derivative.