Separate signers

Hello!  First, you’ll want to set the Signing Order when sending the envelope so you can define who signs first, second, etc.  Here’s an article for Signing Order:  https://support.docusign.com/s/document-item?language=en_US&bundleId=ulp1643236876813&topicId=kcb1578456479440.html&_LANG=enus

After the 1st signer signs, their signature will be locked for security reasons, but signature fields assigned to the 2nd recipient and beyond should still be clickable by their assigned signers.  Remember, we’re always assigning fields individually to each defined recipient, and they should be color coded so you can tell which fields are assigned to which recipient in the signing order.

You mentioned the 2nd signer needs to send the envelope to a third person.  If your expectation is that they fill out the name/ermail for that 3rd signer dynamically, that would be the “Specify Recipients” action which you could assign.  Here’s an article on the more advanced recipient types to help guide you:  https://support.docusign.com/s/document-item?language=en_US&bundleId=gav1643676262430&topicId=nym1578456299890.html&_LANG=enus

I hope this helps guide you!  You may wish to review our eSignature for Senders guide as well:  https://support.docusign.com/s/document-item?language=en_US&bundleId=gav1643676262430&topicId=lxv1687564231272.html&_LANG=enus