When you receive goods that were ordered, you enter the relevant transaction in module Stock>>Good Received Register, with the following Nominal Ledger transaction (Debit - Inventory / Stock Control; Credit - Purchase Accrual Account).

In raising the Purchase Invoice for these goods, your Purchase Accrual Account with get debited and your Cash / Creditors Account in your Nominal Ledger credited.

The Purchase Accrual Accounts is actually only a Holding Account that will automatically be cleared when you send out the relevant Purchase Invoices, this being probably the most likely answer to your query.