Lisa,
To create a highlight you should open up the shop in another tab. Go to the highlight menu hist create will logged in. Type in a title, description, keywords and have the shop open in another tab or window. Find the items you want to feature and copy the url in the browser, click back to your treasury tab and paste the url in one of the boxes. Do this for a minimum of 16 items and hit save and your done.
As far as new post being at the bottom, I changed your profile and now new posts are at the top.