To import dimensions for your products when an order is imported into ReadyToShip, you'll first need to create Metafields in your Shopify store.
In your Shopify store, click on Settings in the bottom left corner.
Then click on Metafields and metaobjects in the left menu.
Click on Products, then Add Definition.
You'll need to create one definition each for Length, Width and Depth.
Select # Integer in the Type field.
In the Category assignments card, click the Assign categories button and complete the following steps:
Select one or more categories from the category picker.
Click Done.
Click Save.
Once you have set up one metafield each for Length, Width and Depth you'll need to populate those dimensions in your products so that when we import orders they also import.