Speedy attendance and payment tracker - junction table?

Hi coda community. I’m a newbie to Coda (coming from Airtable) and am seeing huge potential for lots of areas of my work.

There’s one issue so far I’ve been getting quite bogged down with, and I imagine it will be quite obvious for more experienced Coda-ers.

I want to:

  1. Quickly input attendance at classes from lots of people (up to around 50 per class) in a classes table.
  2. Quickly input payments from people for said classes (as well as termly payments, which I have left out of this embedded doc for now to simplify things…) in a payments table.
  3. Boil this down to one line telling me who (if anyone) has missed a payment for a class

I believe the way to do this is through a junction table in which case I would want a button to send lines from the classes and payments tables to that junction table. I’ve almost achieved this but got stuck on the withname() and formulamap() stuff.

I’m also aware I may also be going down an unecessary garden path here.

Any specific formula help for the buttons or general design guidance gratefully received.

Sample doc :

Hi @David_Walter, welcome!

Could you update the share settings for the doc to allow anyone to edit as at present it cannot be accessed.

Oh sorry :face_with_peeking_eye: Done that now!