Hi Teri. There should be a bar at the bottom of your screen that doesn't move and it has a heart and says I want to do this. If you click the heart it will save the project for you. Hope that helps!
As above, with the exception of the collection of projects. In those cases you have to search the individual project and then the "heart" will appear.
To retrieve, hover over your icon "T" and you will see saved projects. Click on that link and all projects will be there.
If you like a project you can comment on it. To save do the above instructions.