Editing permissions:

Admins and owners can edit any project.
Group managers can edit only their groups' project
Project managers can edit only their active projects
Simple users cannot edit projects.

From the projects list, select the project you would like to edit by ticking the box next to its name.

By clicking on the "Bulk edit" button, you could add new users or associate a client with the Project.

Click on a project to open the Edit Project view:

Basic Info: you can change a project name by typing a new one in the Name box and changing its color (shown in the entries recap and in pie charts) by selecting it from the Color drop-down menu.
Phases: here you can set budgets and choose a category for each phase of the project.
Members: similar to the phase section, here you’ll be able to give permissions and set a total number of hours for each user in the project.
Groups: here you’ll be able to manage the groups assigned to the project