Help w/ an experiment!

I'm extremely sorry if I'm wrong here but I just... couldn't find any other science forums and I really need help with this project I'm working on for school. I'm conducting an experiment on the expansion of non-alloyed metals but I'm having a really hard time w/ the tool I'm supposed to use. Does anyone know how to use a "dilatometer"??? My teacher is pretty much useless and expects us to do everything on our own so I really have no one else to ask. If it helps,this is the tool I mean.

Pls help