That's a broad question.  Read the manual.  If you want to track Fixed Assets you need to buy some Fixed Asset software that integrates with PO.

Using a non-stock item will allow you to specify where the debit part of the transaction goes - asset account or expense account.  The credit will of course to the receipts clearing account until the invoice is entered against the receipt - moving the credit from receipt clearing to the A/P control account.  Once the debit is in the asset account, tracking and depreciating will require manual JE's or a Fixed Assets solution.