The syntax for that kind of thing would be to add the following to your current exists filter.
line 4: EXISTS:a:DE:projects:YourCustomField=_____
line 5: EXISTS:a:DE:projects:YourCustomField_Mod=<your modifier>
The reason is below.
https://experienceleague.adobe.com/en/docs/workfront/using/reporting/reports/text-mode/reference-col...
Your original filter is this:
1) EXISTS:a:$$OBJCODE=PRGM
2) EXISTS:a:ID=FIELD:programID
3) EXISTS:a:projects:categoryID=<your custom form ID>
The first two lines are the traditional lines that start off an exists statement.
1) You identify the object you are linking to. In this case, program
2) This is my linking line, and says that the program's ID is linked to the project's programID
The third line is the filter.
3) This is actually a collections filter. Now that you have linked to your program, you're searching all the projects within that program to see if there's a project with a specific custom form.
The fourth and fifth lines will also filter on the same collection. A way to think about it is, now that you have your project with the custom form, you'll also be picking out a particular custom field and additionally filtering on this.
I can't really give you any advice on the modifiers and such, other than to say that whatever you would normally filter for in a project report, use that filter, convert it to text mode, and the bring it into your exists statement that way, so that there's nothing to guess where the modifiers are concerned.
