/diy/ - Do It Yourself

Hello /diy/. I'll be moving out soon and I want to get rid of my old broken bed. I'm planning to build a plataform bed. The thing is I don't want to use nails or glue. I have at my disposal files, handsaw, hacksaw etc. I plan on using 4 boards and using the wood square grid thing that holds the matress from my old bed. I want to know what kind of cut should I do on the edges of the board to fit them like the pic so they don't slide or move.