In order to display bundle on product detail page with Shopify online store 2.0 themes,
You need to place an app block through theme editor.
Step 1 – Click on “Online Store” > “Themes” in Shopify admin left hand sidebar.
Step 2 – Find and click “Customize” button to customize the theme.
Step 3 – Choose “Products” and then product template from top bar given in theme editor screen.
Step 4 – Click “App block” link given in left hand side at last of Product Information section.
Step 5 – Choose the app block of a bundle you want to display. If you want to display Quantity Breaks bundle than choose Quantity Bundle. Also you can drag and drop that block to reposition the bundle.
Step 6 – Then click “Save” at the top right corner of the screen.
See How 👇