You need to navigate to the [Inventory] and click [Receipts] under [Transactions].
Click on [+] icon.
Click on [+] icon under Details and search for the created child items in [Inventory ID].
Enter the [Quantity].
Click on [Save].
Click on [Remove Hold].
Upon on clicking [Remove Hold] the [Reference Nbr.] will appear.
You need to check for receipt in [Logs] in [Commerce connector].
If you add any [Safety Stock] Quantity in [Inventory preferences] under [Connector Configurations] it will deduct the safety Stock Quantity from the Quantity.
You can view quantity under [Available QTY] in SellerCloud Connector as shown in the below screenshot.