Can't connect and share screen

OK. I’m a dummy.
I have TS installed on 2 Macs. My 2018 mini (Monty) and a clients 2020 M1 mini (Venty).
All I need to do is occasionally look over his shoulder to help him out of iMovie jams.
But I can’t figure out how to share his screen.
His screen and file sharing are turned on.
Tried smb://sonso @100.##.###.## no joy.
Should I be using vnc or something else?

Try vnc:// instead of smb://

nope. Tried with and w/o name@100.##.##.##. NG.
Does the remote computer need to be in my network/admin console as well?

Assuming you are talking about the Tailscale admin console, then yes, both Macs should show up there. Are they logged into the same account? If not the ‘client’ account should ‘share’ that Mac with your account.

thanks. I’ll try that.
2 different accts, though easy enough to put into 1.

yeah, they either need to be in the same account, or shared. If someone else ‘owns’ the remote Mac, I would use share. If you own both, then same account is probably fine.

excellent. I’ll make those changes.

k. that works. connected.
he has 2 screens, I have one.
is there a way to switch back and forth and see them larger scale?

If it was on Windows, the answer is yes…but I am not a Mac person, so I don’t really know. I imagine that there is a way to make it work though.