It is easiest to work on a non-stick surface such as the backing from a sheet of labels or stickers. This keeps your trivet from sticking to your work surface while it is drying. Arrange your corks in rows on your non-stick surface. The top row will have one cork, the second row will have two corks, the third row three corks, the fourth row four corks, the fifth row five corks, the sixth row six corks, and the seventh row seven corks. The eighth and ninth rows will each have three corks. After you have arranged all of the corks, remove them one at a time, squeezing a line of glue between each where they connect and replacing it. Eventually the corks will all be back in place, and there will be glue between them on all sides where they connect. Leave the trivet to dry overnight. When it is completely dry, place it on the green felt, and draw around it with a piece of chalk. Cut out the felt about 1/2" smaller than the chalk line all the way around. Glue to the bottom of the trivet, being careful not to make the glue too thick or it will seep through the felt and show.
After it is completely dry, your trivet is ready for duty! These trivets also make a nice hostess gift if you are going to a party at someone else's house. Please let me know how you like it if you make one. I use mine every holiday season!