This function is under development. Until this DvP function is launched, you can use the token sale function as a DvP contract.
When a buyer buys an asset from the seller, there is usually counterparty risk involved. Either the buyer makes the payment as a first step and waits for the delivery of the asset, or the seller delivers the asset and waits for the payment.
In both cases the counterparty may go bankrupt or simply disappear before the transaction is fully settled.
Programmatic and instant delivery vs. payment (DvP) allows you to eliminate the counterparty risk from token transactions. The DvP contract that you can configure acts as an escrow. Each party will only receive their tokens if both parties have transferred their respective asset to the DvP contract.