To send multiple documents as a bundle for signing select them using checkboxes on the left and then click on the "SEND FOR SIGNING" button at the top.
In the next step, you can reorder your documents to make sure they appear to your signers in the right order.
Click on "CREATE BUNDLE" when you are finished.
A new bundle will be automatically created and the "SEND DOCUMENT FOR SIGNING" dialog will pop up.
Now you can send your bundle for signing in exactly the same way as you would do with a regular document: enter the signer's email address and click on "SEND DOCUMENT".
When your signer will receive the bundle and open it they will see it as one merged document, which consists of the pages from the first document followed by pages from the second document.