At this point you should be able to accept contributions from strangers. Write some contributing documentation to help strangers contribute.
If there are exercises that you wish to include in the track, but have not yet implemented, open issues for each exercise. In general, we recommend opening issues for tasks that you would accept contributions for.
We have a special section on the website listing tasks, which are issues with one or more special labels. Having your issues listed on the website is a great way to get more contributions. For more information on how to have your issues show up on the website, check the tasks documentation.
It could be worth opening separate issues for the things you wish to tackle.