Are you talking about moving plants already on your list into the categories you've created? If so, you need to go into "manage your own list" and click on the little pencil icon on the right hand side of each item on your list. That's the "edit" button. Scroll down a little and you should see a list of the categories you've created. Check the appropriate box and be sure to click the "save your changes" button at the bottom of the page.