How to select an item from relate popup?

Hi All, well 3rd time ive asked a simillar question, hopefully someone will help!
i can make the relate pop up appear but i cant select an option in the box??
Any idea how to do this?

so ive managed to add the link in metadata - but it just closes the popup box - doesnt actually connect the box called “sku or leaflet number”…

pretty gutted im not getting an answer to something so simple here…

Where is the name for the PDF Template? If you had that displayed on the list view of the popup, you should be able to select the PDF Template as required.

Hi Will im using PDf templates module
ive got my field name product ID to have a link in meta data which it does - it justdoesnt fill the box from where the relate field is - named “sku or leaflet number” in my screenshot

Any luck on this issue.
i Have a custom module where there is a field related to documents. In that custom module, i cannot select a document from the popup screen. There is no select option nor a link for the document name to select.

Any easy way to solve this ?