First of all, I'm not a computer geek at all, but I have to understand that term in English, so please tell me?

If you use Microsoft Windows, click "Properties" on the pop-up menu (that is appeared by a right click on "My computer") to show "Properties settings" where you can specify/set information of/about/for/in  the computer.

Which verb and preposition are appropriate?

I would probably say something like, "the properties menu allows you to change your computer's settings" or "you can change the settings of your computer using the properties menu."

There are a number of possible ways to say this depending on the exact context.
Thanks for the natural ways to say, RayH.