how do you on screen recording?

If win+g does nothing, game bar is probably switched off - settings, gaming, xbox game bar. And check the mic button in the capture panel before you start, otherwise you get the system sound but not your voice.

Win and G opens the Game Bar, and Win + Alt + R starts and stops the recording without you having to open it at all. The catch nobody mentions: it only records an app window, so it flatly refuses on the desktop or in File Explorer. Open the thing you want first, then hit record. Files land in Videos, Captures. If you're on 11 the Snipping Tool records too now, and that one lets you drag a box instead of taking the whole window.