How do I attach a file to a form created with DC Pro being sent out for signature?

I'm totally new to DC Pro but need to create a "transmittal" form that will require a receipt signature AND have attached files that we are transmitting. The files can be of any kind of format but are documents for the receiver to obtain for compliance of a legal agreement. An example of what we do is send to an outside organization we have a long term agreement with our Quarterly Operations Report. The cover sheet of this transmittal (by email) is a description of the attachment and a place for them to sign as received. When I created the transmittal form and saw I could "Add Documents", it brings the attached file in as part of the pdf form I created. NOT what I want. I need to track this transmission and get the signed receipt back and want to do this in one email.  Help.