How Do I Start Building My Game?

When he says he wants to be a video game developer, what he means is he wants to make games like Toby Fox's Undertale. So you download the zip, you double click to unzip it and then you double click dragging Ruby EXE and you're up in running. There are two sample apps that that demonstrate how to do a top down RPG with like map collision movement around the map. But I post the link to that. And if you gotop down starting point and look at the source code, I think you'll find it really approachable.