okay.....from how it sounds you seem to have got yourself pretty confused here!!
By creating a form your also creating a way to display your current records.
The forms you have tried will be showing current customer records... however if you click right on the record navigation arrow untill you've scrolled through all your records... and then you should reach a blank record...fill this in and...your done. A new record.
Your using your form to display records from your table...You can also delete, edit and add records in your table from your form.
The fact that your form displays current records shows its correctly linked ...(by control source) to your customer table...
To have the form open automatically on a blank record..then place this code in the 'on open' event of your form
Private Sub Form_Open(Cancel As Integer)
DoCmd.GoToRecord , , acNewRec
End Sub