What does minimize compliance index in Optistruct Optimization mean?

Hello everyone,

I have a question regarding to Optistruct for Structure Optimization Tutorial: Exercise 2a. First of all, I do not found its model file slider.fem in the optistruct tutorial model folder so don't really have a chance to run it. Can anyone please tell me, after setting multiple load steps as compliance index in response, what does it suppose to mean by minimizing it in the objective? Also, I noticed that the Exerice 2a set frequency as constrain. What kind of results we would expect by setting it like this? What does it supposed to mean by minimizing multiple load steps, as load step is just a group of BCs, in my opinion, inside of volume or mass or any variables? BCs are conditions. Why minimizing conditions?

Thanks