Webshipper labels is a dummy label setup, that allows you to create a shipping rate like "Pickup in store".
Webshipper labels uses a dummy label, that simply sets in the information of the customer.
To create Webshipper Labels as a carrier, you will have to do the following:
Navigate to Webshipper > Settings > Carriers > Webshipper Labels
Now you can simply just create the carrier, and you will be able to create shipping methods using Webshipper Labels.
Congratulations! You have now created Webshipper Labels as a carrier!