If the Yu-Gi-Oh! DB website asks to login with Game Card ID just click "I don't have a game card ID" and fill some basic information to proceed
Export Guide
- Via the MDM extension (Recommended): Download on Firefox, or Chrome/EdgeAfter using the extension, go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it
Once the deck page loads click Edit then do one of the following based on the platform your device is running:
(PC Only): Press F12 to open the browser console => Paste the export code there => Hit Enter
OR (Other platforms/PC): In the address bar of the current tab remove the URL and type "javascript:" without the quotations then paste the export code and hit Enter
Save the deck
Go to the Master Duel game => Main menu => Deck option => The Card database option at the top right corner => locate the deck you exported and copy it