If that's your goal, being an entrepreneur is not the way to go. Especially start-up entrepreneurs work an obscene amount of time and most of them fail at making money.

For your purposes, you don't need business skills, you need investment skills and you have to save money. Save as much as you can, don't get into debt, reduce spending and save your money in assets that will generate regular revenue. I have trained professionally about finance. I don't know many non-academic books regarding finance and personal finance for a beginner. Maybe our friends here can share their favorites.

If you haven't read it, Tim Ferriss' four hour workweek might give you some ideas though.