If you’ve never had a computer I guess the concept of downloading and installing programs may seem foreign. Especially if you are used to web apps that just works in a browser window.
Krita is not that, Krita is an old-fashioned program that needs to be installed on a computer or an Android device.
What you need is a community that doesn’t care which software you use. Krita Artists is specificly for Krita, so posting other stuff here is not sustainable.
Are you familiar with Discord? There’s a server called Art Club that seems to be full of friendly people. There’s a channel called “Critique” that would be perfect for you.