well, by changing its resistance proportional to support strain. As in fact all strain gauges this is the reason they are called "strain " gauges! The only differences are a VERY high gauge coefficient (150) and a very high sensitivity to temperature as well in gauge coefficient as in the nominal resistance value. And that's all. For more you have to make 3 steps:
1- open google
2- type semiconductor strain gauges
3- read the docs
So you will become an expert in this technology!!!!