How do I create a single link that multiple participants can use?

This is called a Group Link. You can create a Group Link from the Dashboard or from the Manage Groups screen. 

From the Dashboard:

1. Choose your assessment from the dropdown menu.
   
   
2. Select the Create a Group Link radio button.
   
   
3. Enter your group name.
   
   
4. Add any desired link options below.
   
   
5. Click Create Link.

Now, navigate to the Manage Groups page and you will see the group, assigned assessment and the link. You will also be able to copy a QR code for the link if you want to use it in marketing or presentations.

From the Manage Groups screen:

1. Navigate to Manage Groups from the left menu.
   
   
2. Click Create Group in the upper right corner.
   
   
3. Give the Group a name.
   
   
4. Choose whether or not you want to a Group Only or a Group with a Link.
   
   
5. If choosing to Create a Group with a Link, choose that radio button.
   
   
6. Select your assessment from the dropdown menu.
   
   
7. Add any desired link options below.
   
   
8. Click Save.