You can't, unless you know their user ID. If you do know their ID, you click on "Advanced" at the right of the "Search" button. Then, you select "By Seller" on the left side of the page, enter the username and click "Search".
Do you check the group session? Or start one of your own, others could share their experience with ebay. Seamstress-fredette, plenty for me to learn here, before selling/buying.
