Checkboxes using Join Table
I'm trying to set up something that should be very simple, but can't seem to do it. There are two tables "Documents" and "Sites". I want the Documents layout to display the available sites (currently only two) with the user able to select which site(s) apply via a checkbox.
Following other advice on this forum I've got this far: set up a join table (Doc_Site). Checked "allow creation of records" in the Doc_Site table via the relationship. Then set up a portal to the Doc_Site table on the Documents layout. In the portal I included Site ID and Site name, both from the Sites table. However, this portal does not let me enter new data. I've also tried setting up value lists but this didn't work. I set up the value lists through the "inspector". Was that the wrong place?
Other advice on here linked to a Demo file. Unfortunately I could not understand it. The Check Boxes tab says to use a portal "using the Cartesion join operator "X". I can't get past this step. What exactly does "Cartersian Join Operator X" mean, and how to do it step by step? Is there a simpler way to do this?