Active Lists and meetings/next/last activity (new user and pointers much appreciated)

Hi
I’m trying to set upa booking system PoC, using Active Lists that email people to invite them to book a meeting, I’ve set up a meeting page, and some forms in Landing Pages and theyre working really nicely; Registration form>meeting booking, and a standalone meeting booking page to be added to the Active List emails.
1) if they created a lead record (Register) more than 2 days ago without booking a meeting.

2) if they havent got a future meeting booked, their last meeting should be 2 days ago but their ‘next activity’ should be 'unknown, but the - in the next activity field may be throwing that off.
Im very new to Hubspot - any tips or hints of functionality that I should look

I just cant seem to get these to work at all, any advice very gratefully recieved.

Thanks!

Hi @rogerfarrow7,

Can you try the list criteria below? (Replace ‘Any form submission’ with whatever form your contacts usually register on.)

Hope this helps!

Thank you Karsten, that was so helpful, I wouldnt have got to that combination of fields without your help and its looks like its working really well!