Get yourself a project. Any project, but preferably not too minor. Write that project in your new language. Many times while doing that, you will need to do a few days or more of solid studying of the new language to get yourself past a hurdle that's blocking your progress.
Eventually, you will complete the project. Now, throw that one away. It was just to 'show you the ropes'. (That's commonly said as "Build one to throw away.") Now do that project again with your new, greater, basis of knowledge.
Repeat that with several projects. You now have a fair level of self-taught programming in that one language.
Repeat that process again but using a different language. There will be hurdles again, but different hurdles.
Now you know programming to a reasonable level.
Rinse, repeat. Rinse, repeat. Rinse, repeat.
Solve the problem.