To get an overview of the details in a workspace use the About Sidebar.
Access it by clicking on the info icon in the top right corner.
Minimize the About Sidebar by clicking the info icon again.
When the sidebar opens you’ll see a blue ? icon which provides access to a Help video walk through.
Click on the Members header to expand the list of members that are in this workspace.
Click on the Profile Card to view their email, phone, and location.   
You can remove a Member by clicking the “x” icon to the right of their name.
Or you can add a Member by clicking the “Add members button”.

Note: If a member of your team does not show in this list, you need to send them an invite so they can join the team, before they may join this workspace.