Hi Rebecca, is this what you’re looking for?
If so, you can find the base here. To view the formulas, duplicate the base by clicking the title of the base at the top of the screen and then click the three horizontal dots on the right
You mentioned the master sheet needs to link via the surname and email, and as a result we create a formula field that combines those two things together that acts as our new unique ID for each record, and we do this for every table.
After that, for every data sheet, we can simply paste this unique ID into the field that’s linked to the master sheet and it’ll be linked automatically
Let me know if this isn’t what you’re looking for and I’ll see what I can do!