Sign in first
Might be easiest to click on link below then bookmark it:

http://members.gardenweb.com/members/
You will see clickable choices that include "Edit Your Exchange Lists" (4th choice down if you have signed in first)
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If you are at another computer without all your bookmarks:

Sign in, click on big white "Garden Web" words at top, click "Member Pages" in tiny white font near bottom right (gets you to bookmark above)

You might prefer to type your Want List in something like Notepad and then copy & paste each line into the bullets of the Want List, whatever way you prefer.
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If you continue to have problems, click the link below and ask Tamara, who is something like Community Services Director as well as our Tech support - gives me lots of support!

Gardenweb Contact Us form:

http://letters.gardenweb.com/letters/mailed.html
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Then post back here when you get it to work so we can see what you have to trade! Hurry back!