Do you know what stock adjustment account to select when you are going back and entering your initial cost on stock starting values to items in stock asset account?

cost has to come from somewhere, do not do this with an adjustment

so put that cost in a cash type bank account, and buy the items using the items detail part of an expense form, enter the item, qty an total cost

If this is starting value, you can make a deposit to the cash account in the total amount and use owner equity as the source account for the deposit - assumes you are NOT taxed as  a c- or s-corporation