This question is in reference to Atlassian Documentation: Assign users to groups, project roles, and applications
So, I just barely started my JIRA account and I'm learning how to use it. I created a project, updated my backlog, and created a sprint but now I want to know how to add my client as a user and restrict their access to only this one project. I've read a whole bunch of documentation on how to do this and I've tried about 5 different things but it still is not making sense to me. Can anyone help me with this?