When you setting up your account, this data needs to be filled like Default settings, Tax, Currency and Orders (customize select pick list) in General settings page.
In this you can upload your barcode and kartzHub automatically add those barcodes with the product when you list the product. You can see all your used barcodes in Used Barcode option.
From this page, you can set up automatic sync of all your product quantities and updates in all integrated Channel. You just need to click the box what are the Channel you want to Sync automatically.
If you are managing your orders via a Fulfilment Network such as Amazon FBA please add your fulfilment network details here.
This page gives you the provision to set up your email server settings through which all the emails will be sent to user customers.