How to give access to users to Projectpier?

I have installed the Projectpier and completed all the necessary steps.
I have added Company, Members, Projects, Tasks, Milestones everything, but I don't understand how to give access to others so that others can come and put new tasks, send message etc.

I even tried to send the messages to users newly added, but those messages are not delivered to specified email ids. I am using default PHP settings to Mail Transport.

Please help.