As a customer you need to be logged in to interact with the order proposal. When you navigate to My Account in the right corner on top and then on Orders on the middle left side of the screen.
If the shop owners created a proposal for this specific customer, he sees the following order.
He can see the order like any other order one. On the right side two new actions will appear: Accept Proposal and Decline Proposal.
If the customer accepted the proposal, the status of the order switches to Pending Payment. There will also appear the two new actions Pay and Cancel.
If the customer declines the proposal, the order’s status switches to Cancelled.