crafting fences

I'm doing this project on survival mode for school, and I have to build Solomon's temple. I live right next to a desert so I was thinking about building it there, but I need to find a spot. How I'm going to mark it is with a little "flag", being some fences and a block of wool. So then I decide to start finding a spot, but then that's how I realize I can't craft fences for some reason. I put the right recipe into the crafting table, but nothing happens. I have tocollect naturally spawned fences. Please help.

Thanks in advance,
mariocoin