First, if you haven't already, you'll need to create a group with the users that you want to run a report on.
Just go to Groups and hit Create New Group.
Next, name your group and add the users using the Members tab.
Now all you'll need to do is run the Report. Choose Group.
Then Summary of a Group.
Then just choose the Group.
Choose the report you want to run, click Next Step to run the report, and you're done!