I know absolutely nothing about music. I know what a chord is and that’s about it. What do I search up? Where? All I get from people is ‘just make music bro u gotta feel it out’, which does not help. I can’t just put together random instruments and random notes. What can I do?

I'm curious about the technique for strumming down on the 'and' beat. Do you break the natural swinging motion of your arm when doing this? Also, what’s the correct term for the 'and'?