OK - things can be setup as you requested but you need to delete any Inventory Item transactions and then un-tick the Inventory Item tab under customise. Also you need to have entered a date under Settings - Start Date.
In the BS Asset section you create “one” account called Stock on Hand (NOTE: do not create separate opening/closing stock accounts in the BS). To enter the opening stock value go to Settings - Chart of Accounts and click "Edit: next to Stock on Hand, then click Starting Balance and enter a value & Update.
Next you create your P&L Chart of Accounts to reflect the Gross Profit as illustrated below
Noting the following 1) Cost of Sales is a new group, 2) Gross Profit is a new total and 3) the light grey numbers are the codes used to get the layout/structure correct.
Throughout the accounting period you allocated all purchases to the Purchases account. The P&L Opening/Closing Stock accounts are “only” used to make any valuations adjustments at the end of the accounting period and the Journal would be with the P&L showing:
