Starting at your summary page in Listing Mirror, click on your Walmart edit listing page. In the example below it is the gear logo under the Walmart column.
From here we need to click on the (1)“Category” tab found on your Walmart edit listing page. Then you will be able to fill in the (2) brand field.
Other required fields will be marked with a red *. Complete these fields
If you are seeing a lot of these, you can do a bulk edit, by going to your Dashboard Menu > LISTINGS > Bulk Edit Templates ... then choose 'Category Specific Add/Update, then the appropriate integration. Download the template, fill it in then Upload it using the same page.
If you have any other questions regarding this process, feel free to reach out to Listing Mirror support.