You cant assign autonumbers for access it's going to assign them itself how it sees fit and you shouldn't care about what the numbers are. Those numbers are for access' use and you shouldn't be using them for anything. There's a video on here if you search for custom sequential numbers that might tell you what you need if you need an "autonumber" that you actually care about. Ill link it when I'm back to a pc.

Otherwise you could make a field in your excel table and import it into a number field in access, not autonumber

Thank you for your response Adam.  How do I add records to the Access table using excel?  I thought the fields to be imported into Access must be identical for the import to be successful.

I've done a lot of imports with excel and changing what field they go into at the time of import.

Try this video Import Data

This one might also help you Import New, Changed Records and heres the custom sequential numbering if you want it Here