To assign a signature to a group, click on the "Signatures" tab of your Letsignit platform.
Select a signature or click on "New signature" if you want to create a new one.
To assign a signature to a group, click on the group section on the left of your screen.
Select the group which you want to assign the signature. You can also create a new group on the "Create a group" tab.
If you want to know more about the group creation, click here