Setup a form to enter the data and then add a button field to your table to open the forms url and pre fill the form with the correct data to link the records.
Add your button to the interface. The form will open in a new browser window. Submissions will enter the interface view if you’ve done it right.
Extra tip - If you set the form for multiple submissions the pre fill data persists across the submissions, allowing you to add multiple linked records in one session.