Step 1: Tools
1 pic: table saw
2 pic: compresor
3 pic: Compound Miter Saw
Step 2: Preparation
Cut them to desired height and width.
Make a pointy thing on the top.
Then make a frame, you can use any long boards, i used 1x2 boards.(i think). I used 2x4s for the ones that went into the ground.
Step 3: Nail The Boards
But first, nail two boards at each side of a fence and nail a long board to the top, make sure it is leveled.This will make it easier to make them look all even. Leave an inch between them.