Currently numbered tabs are only available in the 'Legacy' template.

You can add numbered tabs to the top of multi-step bundle pages to help customers easily navigate back and forth and make changes to their bundle. This is in addition to the standard Next and Previous buttons.

Navigate to your Bundles, click on the bundle you'd like to edit (or create a new one) and click on the 'Design editor' in the top right of your bundle.

Select the 'Legacy' template and you'll be taken to the Design Editor.

The 'Multi-step bundles' section is where you can setup how the numbered tabs will look.