MikTeX Installation

Its strange that the command line does not respond to the latex command. I suspect you might have unchecked an option while installing.

In any case, there are two ways (+one) to try out and start learning latex:

a) The "Hard" (if you want to use latex in the command line)

add the path of the miktex bin folder to the path of your machine

b) The "Easy" (if you just want to try latex without the cli hassle).

Just install an IDE like Texstudio, Texmaker, or a few others (free and commercial) available.

c) The "Easiest" (if you want to learn latex without installing/updating anything on your pc)

Just to the Overleaf create an account and start trying things out.

I didn't bundle the third option, with the other because you already have a working miktex installation.