You will need to buy a tripod head and mount it on the stick, cost about $20.00. Most of the parts to build it will be less.
There is a PDF file with instructions and the parts you will need. The DIY indicates it will cost about $45.00 total.
Its a cheap way to get stable video while walking or even running. A fun little spring project to get you out and shooting again after the long, cold winter.
Here is a video showing how to make a similar steady camera stick, this one includes a bolt to hold the camera.