Hi Ronnie,
You are able to add more than two contacts to a Customer using the Import Tool in Method. You can do this by using the "Contacts" table, so if you want to first export this table, you have to make sure you uncheck the "show only common tables" from Step 2, "Pick a table". You will be required to include, as a minimum, the Company Name, Entity, and Name fields. Make sure your Entity name is the same as the Customer Name that you would see if you went to edit the Customer from within Method. I have attached a screenshot below of a .CSV file I imported to the Contacts table after making some modifications:
I hope this helps, please let me know if you have any further questions to accomplish this.
-Ben