Criteria Help

Hi All

Fairly simple one I think...

I have created a lookup field on a new form. I want to set a criteria so it only shows values from records that are invoiced. i.e. I have a form with lots of field, one of which is 'Invoiced?' - simple Yes/No. On the new form I want to look up the those records, but only show records which have the Invoiced value of 'No'. The lookup is a different field by the way, not the 'Invoiced' one. Hopefully that makes sense?

I'm not familiar with Deluge, so what do I put in the criteria box to achieve this?

Many thanks

Nick