Welcome to the community, @Steve_Littleton! :grinning_face_with_big_eyes: You put this pose in the “Importing / Exporting” category, and to my knowledge Airtable’s import tools shouldn’t allow record overwrites. However, if you’re doing a literal copy-and-paste operation to add the data into Airtable, then you’ll need to take the necessary precautions yourself to prevent the overwrites from occurring.
Airtable doesn’t have an “insert” mode when pasting, so attempting to paste into the middle of an existing batch of records will overwrite anything below your paste point. To add without overwriting, scroll to the bottom of your records, add a single new empty record, then paste into that, and confirm the prompt about adding more records to accommodate the data that you’re pasting. None of your current records will be overwritten if you use that method.