In order for the tag to be activated on your Walmart listings, you'll need to configure 4 shipping overrides per listing and set lag time to 0. This can be done within Sellbrite.
To do so, please navigate to your Walmart listing and click on "Shipping":
Select "Add a Shipping Override". Please apply the following 4 shipping overrides:
1. Disallow Standard:
2. Disallow Value:
3. Disallow One Day:
4. Enable Free, Expedited:
Then, you'll want to set lag time to 0. To do that, navigate to "Options", and set "Fulfillment Time" to 0 days.
Then re-submit your listing with the shipping overrides and lag time update. It may take over a day for the shipping overrides to take effect.