I'd like to import two contacts to a deal. How can I do it?

I uploaded first the Account, then the two Contacts  (which both appear in the Accounts), but when I upload the Deal, I'm not visualizing there the Contacts and I'd like to also visualize them in the Deal. How can I associate these 2 contacts to the deal in the mapping while uploading it?

Looking forward to your response.

Thank you and kind regards,