Summarize this article:

If you are making your pipes out of bamboo, buy as many stalks as you need. If you live in a warm climate that grows bamboo, you may be able to find bamboo outside or at local shops. If you don't have access to bamboo in your community, order it online. Make sure each stalk of bamboo has around a 5/8 inch diameter.  It's important that all the stalks have a similar interior diameter, or else it will be hard to make them sound good together. Make sure the bamboo isn't green, and instead is dried and tan in color. Take a stalk of bamboo and cut it at one end right before the first node using a saw. The nodes of the bamboo are the lines that run horizontally across the stalk that you can see from the outside. The nodes are closed on the inside, so they create a good natural bottom to your pipes. After you have made the cut before the node, use a belt sander to make the outside bottom of the bamboo stalk rounded. This isn't necessary, but it will make the bottoms of your pipes less prickly and spiky, and will also make your instrument look better. Do the same process for all of your bamboo pieces. Use the same measurements for the straw pan pipes, starting with the longest pipe at 17.5 cm and the shortest at 8.5 centimeters. Use a ruler to measure and mark these measurements on the bamboo. After forming the bottom of the pipes around the node, you will want to clear the inside of the bamboo, still keeping the bottom node untouched. Since nodes are closed on the inside, they will stop air from going through the entire pipe and will interfere with your sound.  Use a steel rod with roughly a 3/8 inch diameter to break through the nodes inside of the bamboo shaft. An effective way to do this is to clamp down the steel rod, and then take the bamboo shaft and poke the nodes out using the rod. You also will want to use the rod to scrape around the inside of the bamboo nodes so that the inside node area has the same interior diameter as the rest of the stalk. Using the measurements you already marked down, cut the bamboo into differently-sized pipes. Remember that it's better to cut your pipes a little too long than too short, because you can always do another cut.

Summary:
Pick out or buy bamboo stalks. Cut the bamboo in front of its first node. Sand the node area. Measure out your pipes. Clean out nodes between sections. Cut the bamboo according to the measurements.