You can open Team Activity by selecting Data Manager from the Navigation panel, and then clicking Team Activity.

Team Activity lets you view information about project team members such as the time and date of last access and changes, and how many changes each member made. You can view this information using the default list view ( ), for example,

or you can view the information using the tile view ( ), for example,

You can also search for specific users, as well as filter by All Users or only those team members with locked resources: