How to reference custom admin page not in menu

Hello all WP gurus –

this is a newbie question, so please bare with me. I have written a plugin with custom menu, which works as planned. I successfully created sub-menus which display forms, options, etc. and I can save form data to the database.

Let’s say I have a list of records I can view via a sub-menu called “manage records”. Each record shows various attributes like artist, album, duration, etc. I have added a column with “actions” such as “delete, edit” as HREFs for each of the records, identified by a unique ID.

One thing I am drawing a blank on is how I can make the “edit” href load a record, that is saved in the DB, and display its values in a form?

Creating the records is done via add-records.php and I have all the form fields, I would need for editing. Yet I was thinking of creating a update-records.php page, which strictly handles update operations to the records.

Any thoughts or pointers? I looked online and could find a ton of info on how to create menus, yet nothing that would help me in my situation. Help is much appreciated.