You can to enter at distinctive Deep Web markets only with an alternative link, that suggests a tricky situation : upcoming customers and vendors don’t have a possibility sign up until they will receive an alternative link from an previously enlisted user.
Look at https://darkwebonion.com/, it stores new alternative URLs to concerning Dark Web markets. You should follow these URL to register on the sites.
If there are some troubles with an access (links don't work), you shall wait and check for Deepweb markets alternative links. Keep trying, as few marketplaces may stop and open registrations from time to time, due to server load.