Greetings!
I would start by suggesting that you only think in terms of participants, and not try to separate "participants" from "signers". Signers are participants too.
The first participant in the transaction can be a signer or some other role. But you have to explicitly assign the field to the participant. Check out this article: Assign form fields to recipients
Hopefully, you are using the drag and drop environment which does a good job if visually indicating the field assignment.
If you are building the form with Text Tags, the idea of the participant uses the terms ":signer1" and ":signer2", but don't let that derail you. The first party to add field content and/or sign the document after it has been sent is participant1 (also known as :signer1 in text tags). The second person is participant 2 (or :signer2).
It's hard to troubleshoot without knowing more about your process, so if the above-linked article doesn't answer your questions, please let us know How the signature cycle should flow, how you are building the form (Authoring, Text tags or Acroforms), and what you mean by building a workflow (because we have a tool called "Workflow Designer", and it has it's own considerations.
-Scott