In the Project Workbench use the Project Allocation tab to assign or allocate Resources to Projects.

First, select a project. You can search for the project by name or code.

In the Resource Tab, assign an individual Resource to a Line or Deliverable.

This is the person, who does the work or is responsible for it. You can search for the Resource by name or restrict the display to a particular resource group.

You can also rotate the display for easier view.

In the Allocation Tab, select Resources that contribute to the project line.

If enabled, only Resources assigned or allocated to a project line can select it for Time and Expense entries.

If you only manage access, there are a few shortcuts available:

To give access to all users for a Project, select the Share All Lines checkbox on the project. If selected, the background of the allocations turns light green.  Examples for this are internal projects like education or vacation.

An individual Resource can Access All projects and lines. If selected, the background turns blue.  Note that this applies to all projects, not just this one. You would select this for people who could contribute to any project.

Lastly, you can select Share All for a Project Line. This allows Resources with access to the project to select this line. The background turns lime green. Examples are Support or Management.

For Project Resource Planning, you would still select and allocate the Resources here. 

The shortcuts are for managing access only.

When done, click on Save.