What can I use to change container views?

[SamaritanMachine]

I have 3 container view and I want to connect these and SJFluidSegmentedControl. I've tried this
if segmentedControl.currentSegment == 0 { firstContainerView.alpha = 1 secondContainerView.alpha = 2 // bla bla bla }
But it didn't work. Can you suggest me a place and method of use ?

[ZahraAsgharzadeh]

I have the same problem too .
If you've found a way , answer me please 👩🏻‍💻