Depending on the thickness of the bamboo, a method I have found useful before is eye screws + cable ties. Screw the eye screw into location you want to fix the branch, drill a hole straight through side of bamboo or branch, feed the cable tie through the hole and out the other side, then through the eye screw and tighten. If the bamboo is not so thick you could even just cable tie around the entire circumference. You can use a file to remove any sharp edges left over when you cut the remainder of the cable tie. This is just a method i put together with materials I had around the house. There are most likely better ways to do it (specific brackets for mounting) but I wouldn't have a clue what to look for.
Alternatively, instead of an eye screw I have previously used cable tie anchors. They are basically a small base that gets screwed to the side of the enclosure in order to allow a cable tie to go around it.