Create an agreement for two signers via Rest API

How can we create an agreement using a library document using a library document which will be singed by two signers? I know how to do the same using echo sign web application using this tutorial: Send an agreement to multiple signers with Adobe Sign​

I have created a template document in my dashboard for reuse purpose and I have added fields for recipients as well. But when I create agreement using that library document and from that agreement I create signing url. But both URLs only allow one of them to sign. If the second signer opens their link, the document shows as already signed. Can anyone tell me how can I create  and have my both signers complete the agreement using Rest API?