If you are just uploading a document that requires two parties to sign, then you use Send a Document, add the document (upload), set two Recipients as Needs to Sign (I would suggest using "Recipient Order"), set any custom emails, then Next. Add tags for each Recipient, using the upper left color coded dropdown, select Recipient 1 (this is chosen by default) and drop a Signature tag, repeat with Recipient 2. Once all fields are added and you are satisfied with attachment, fields, placement etc, Send.