You will want to click on the "Home" button located at the upper left corner of the page, which will take you to your IMleagues account page. From here you will have a list of all the current and past teams you have played on through the Intramural Sports program.
Find the specific team you are interested in adding people to and click on it. Now you will be directed to your team page. Look for a boxed category titled "Roster," and directly next to this title you will see an invite button. Click on the "invite" button.
This will now take you to the invite members page where you can invite a friend to join your team. If your friend does not already have an IMleagues account then you can send an invitation via their email address (UA school email). If the individual already has an IMleagues account you can enter their name into the search bar directly.