It's easy to put a project on hold when you need to pause it for a period of time. Starting from your personal dashboard page, click on the "Manage Projects" button.

Once you're in the list of projects either scroll through to find the one want or search for it by keyword.

Once you've found and selected the project, click on the "edit" link in the upper right corner of the project tile.

Then, to put the project on hold, just click the "Put on hold" link on the right side of the project brief.

A pop up window will open asking you to confirm that you want to put the project on hold and reminding you that you will not be able to edit the project until it is made active again. To do that, go to the project brief page where you found the "Put on hold" link. That will have been replaced with a "Make active" link which you can use to reactivate a project.