Test order is placed to testing synchronisation, this aims to make sure the new Inventory Group has been setup correctly and behave as you expected.
Back to your Shopify Admin screen. Click Orders at the sidebar. Click Create Order button.
Click Browser products button to select one of the product (or variant) from the Inventory Group you have just created. Click Add to Order.
Click Mark as paid to turn it into a real order.
Click Create order to confirm.
Open the Bulk Editor once again. You should observe that the inventory quantity of both the Bundle and Components are reduced. For Components, they should reduce by how much quantity they contribute to the bundle. In this example, the desk is reduced by 1 for each of variant (Frame and Top).
If you find the inventory is not sync, read the Article Why the inventory is not synced? to check all are set in place for the variant is not synced.