How do I know when I’m ready to solve and commit to projects?

There are a few ways:

1. You notice a problem, write some code, compile/run it, and it works. 🎉
2. Download a project with some tests, set up the testing environment, do as per point 1, run the tests and keep fixing your code until they don’t fail anymore. 🎉
3. Do as per point 1, submit the PR… and many people will tell you whether you’ve missed something. Depending on their character, they might be helpful, ignore you, or rarely be assholes. YMMV. 🎭
4. Fork the project. Now you’re in control, so proceed as per point 1. To make your life easier, write some tests, set up a testing environment, make it easy for others to replicate, document stuff, both for you and for others, describe the general architecture to have a high level view of it, and so on. 🎉