Home has an Inventory card. It says "Coming", and there is nothing to press: inventory quantities cannot be edited in metangelo yet.
What you can do today
- Track quantity and Continue selling when out of stock are variant fields. Choose them on Variants.
- Quantities themselves are edited in your Shopify admin, under Products, Inventory.
Dimensions and weight are not inventory
A variant's weight, and the dimensions in your metafields, are edited on Variants. See Editing variants.