Where is the compressor's secret side-chain button in 7.5?

Just getting into side chaining. Pulled up Steinberg’s compressor only to find there is no side chain button anywhere that I can see. Looked into the vst reference guide. It has a nice picture of the compressor, but no side chain activation button there either. However, the documentation given for it says that side chaining is supported on this vst.

Anybody have the secret to getting this thing to do what it purports to support?

I find that the tube compressor has a side chain activation button, but I do not want a tube sound.

See the little orange button?
Screen Shot 2014-08-19 at 11.42.55 PM.png

Thanks for the info.