I started by just changing the existing program and seeing what happened. Seeing the relationship between the little bouncing letter on the screen and the numbers in the program. Made it go faster, or slower, made the bouncing area on the screen smaller.
Then added in a new feature. Can I make 2 letters bounce around on the screen independent of each other. Most of my tries ended in failure, week after week after week, but eventually I got it to work and there were two letters bouncing around on the screen. There was a feeling of joy at that point. Sure, it wasn’t pretty, it was in basic after all, but I had made the computer do what I want. A lifetime of programming was born in that moment.