Gated or locked brands require a buyer to request access before being allowed to begin shopping for products.
You can request access to their brand by clicking on the Green "Start a conversation" button on their brand profile page.
Or on the product details page for any of their individual products.
The status of the connection will show like below.
Once you've requested access and a seller or brand approves you, you can then begin to shop for their products.
If a brand has not recognized your access request in a timely manner, please don't hesitate to contact the brand by referencing the contact information found on the brand page under the logo.