- Navigate to the decks tab in "My Library".
- Hover your mouse over your deck and select the circle in the top lefthand corner.
- Repeat step 2 for all of the decks you want to merge.
- On the toolbar at the bottom of your screen, click the Merge button.
- Enter a title for your new deck. Select whether to keep the original copies of the decks in your Library, and drag to reorder the decks if needed.
- Click the "Merge items" button at the top right of the popup.