If you are part of the group working on the project

Monitoring and enhancing plant growth in space ecosystems | SoC Labs

Then you can join the project in your profile. It is easy to do, just click the action on the right hand side in the project.

You can add milestones to your project at any time. Here is a good example of update to a milestone to add a completion date and show progress. It comes from one of last years projects.

It shows both the Completed Date and key additional information such as the reported area with a clear statement of the inputs that this is not using a specific technology node standard cells.

You simply need to edit the Project and then simply select milestones from the generic design flow stages or create any unique milestones. So taking the first steps in the design flow you type 'arch' and it autocompletes the design flow step needed.