Thanks for contributing!
Please open an issue with what you're trying to do before starting to code. This way we can make sure we're on the same page from the start. Of course if it's a small fix or if seeing the code would make it faster to discuss, feel free to open the PR right away.
When we've agreed on the course of action, you can open a PR with your changes. It shouldn't take long to review, except if I'm busy in real life ^^ But mostly, since I know what the PR is about and if the automated checks are green you can expect the PR to be merged soon enough.
When you submit your code, you'll agree to license it with the same license as the rest of the project. The license shouldn't change, but if it ever does, I'll take reasonable measures to contact all contributors, and if I have no news of you after three months you'll be considered as having agreed to the change.