There are a couple of ways to edit an existing Project.

Firstly, you can click on the Project name from the Project list to view the Project Details. From this page, you can edit the project details with ease by clicking on the field that you wish to edit.

On the Projects List page, you can tick the box to the left of any project, which will bring up a menu that allows you to edit the Workstage, Priority, Tags, Start Date, Due Date, and Category of the project:

You can also hover on the Project and then click the Pencil icon to the right of the Project name to edit the Project name from this view:

Using this tool, you are also able to select multiple projects and make the same edit across all of them.