When someone else on JamKazam sends you a friend connection request, if you are online on the JamKazam app at the moment when this request is sent, you will see a message pop up from the bottom center of the app notifying you of this request (pictured below with arrow).
You can click the orange Accept button in this message popup to accept the connection request. But if you aren't online when the request invitation is sent, or if the message popup disappears before you can click it, then you can still find this request in the Notifications feature (pictured below with arrow).
Click on the Notifications text (pictured above with arrow), and the notifications section of the blue sidebar opens to display any notifications you've received. Click the orange Accept button on the invitation (pictured below with arrow).
The friend request is accepted, and you are now connected as friends on JamKazam. Your new friend is now listed in the Friends section of the blue sidebar (pictured below with arrow).