A reusable template is documents that are created within the Template Library and stored until needed.
When creating a template you will set signer roles, which labels all of the signers titles.
Then, you will set all of the signer fields for each signer role.
Lastly, you will click "Finish" to complete the template and place it into the template library where you can use as you please.
Any time you want to use the template just click "Use this Template" and you will be directed to enter the signers information into the appropriate signer roles.
Reusable templates are best used for concurrent documents that are sent frequently.