I am trialling the board roll up app using Omnitas consulting tutorial vids as a guide and I am looking to aggregate numerical values on a project board. 

I can't seem to select anything for the 'this number' part of the below recipe selection' that will allow me to track things like hours used, hours allocated etc. 

I thought it might be an issue as I have mirrored the columns to give me the total sum of the subitems but when I also tried it on a regular numerical column I have the same problem. Any ideas which step I must have missed?

'watch this number in connected boards and aggregate detailed board items to this column displaying the field number operation. filter items by named filter'