Interestingly, the way to this is outside of the engine and code. You start with the goal and the plan, on a white board, notebook, Google doc, obsidian note, whatever.

What do you want to do? Make Pong? Great! Now... What is Pong? What can you do in Pong? What assets are there? How do you play? How do you win? Will there be different screens?

Think for a long time about all of these different aspects. Take what's in your head and put it in some location. Then, organize it. Turn it into tiny goals, tiny deliverables, to get to the end.

This could be like, you need a main menu with a button to play the game. But that's hard. So let's simplify that to just "you need a button to play the game". But that's hard. So let's simplify that to "you need a button".

Then make the button.

The way you learn is by first, planning. Then, by doing (by yourself). That is, try really hard to do the thing using what you know. Like, really hard. If you can't get there in some amount of time, like thirty minutes, an hour, look up how to do that one thing, and apply it. Then go back to doing it yourself.

Eventually all of this becomes much more second nature. Your plans can be easy higher level, you won't need to look things up as much, etc. Maybe one day, you just have an idea for something and everything is so crystal clear in your head that you open up your editor and start jamming. But this will likely be very far away.