What do you mean? You just type in their email address as the pay to person. It will default in goods mode which means the payment is for goods and not a gift, etc and the fees will be taken out of the amount the seller receives. Very simple process. Your shipping address should also default in the payment received message the seller will receive.
ETA: I've bought and sold hundreds of watches and other watch accessories on WUS and Timezone, and haven't really had a problem to date. I do check out the buyer or seller a good bit before going through with a transaction though.
This post was edited on 3/13 at 9:46 am