Hi @TatKhandM,
In the Custom Metadata screen you need to search for PERSON. If it already exists then great, if not you will need to create a new record for the PERSON table.
Once in PERSON you need a column entry for NACL. Again, if it selects thats great but if not just click new and enter NACL for the column. There is a tick box field for ‘force select’, make sure this is ticked and then save.
Then refresh cache, log out and log back in.
If you need further help with custom metadata then click the question mark in the top left of the screen when you are in custom metadata. This will take you to the user guide for the area.
Kind regards,
Lee Pinchbeck