How do I set up my desktop Teamviewer app to connect with a friend's laptop?

bSMy84

I want to do something that should in theory be fairly simple to do.

I have Teamviewer installed on my desktop iMac and I want to connect it with a friend's MacBook to provide support for him when needed.

I did this in the distant past with my elderly mother's iMac desktop, but I can't figure it out now.

I've attached a shot on my end, and seem to remember that a similar control is also on the computer I need to remotely connect with.

A simple step-by-step explanation would be greatly appreciated.