When you complete a deliverable, you might need to update your client about the same but if you are using Yess, forget about that. Just
set a reviewer and Yess will take care of the rest.
Clients can also set their partners as reviewers
How to set a reviewer?
Most probably, your reviewer would be your client. If not, see this article to add more client partners to Yess.
Click on the deliverable to open it → See a field names
Set Reviewer at the top right side of the page.
Select a reviewer, and your client will get a notification about reviewing the deliverable.
Do more on the project launch page by reading the below-related article.