Step One: Buy 92 cent Wal-Mart cookie sheet.
Step Two: Use painter's tape to layout your design with enough categories for all your lunch options, plus a "home" for resetting the board.
Step Three: Lay out your magnets to make sure you've left yourself enough room. I bought the magnets at Wal-Mart too and they have foam adhesive on one side. I thought this would help with the next step.
Step Four: Replace ugly painting tape with cute 88 cent decorative tape from Wal-Mart's back to school section now that you're sure the layout works. If you're like me, you'll also decide that you want the magnets to move from left to right like reading a book and flip your entire tray around. ;)
Step Five: Peel off the adhesive backing and add colorful sticker labels (you know, the yard sale kind) to your magnets. Number them for each student.
Step Six: Use a marker to label the sections with your lunch choices. I used a dry erase marker so I could change them later if I needed to, but it kept wiping off so I switched to permanent marker.
Optional Step Seven: Make one for the really awesome new teacher down the hall who said she wanted one too, but we all know new teachers have enough other things to do. =) She has a rock star themed room, so I used tape that matched her colors. It was also 88 cents at Wal-Mart.
I was able to make both boards for less than $5. Money well spent!