Follow this steps to add an user to the project:
Step 1:
On Settings, click on Users.

How to add a user account

Step 2:
You will now see the existing users, as well as their profiles and email addresses.

How to add a user account

Step 3:
Click on Add user.

How to add a user account

Paso 4:
Fill in the fields shown on the screen and click Save.

How to add a user account

Once you have clicked Save you will see the main menu, in which you can see the existing and new users.

How to add a user account