Help needed with SC4 plugin

I’m running Audacity 2.0.5 on Windows XP (yeah I know I need to upgrade.) I downloaded the SC4 compressor plugin a while back but I have no idea what some of the parameters are supposed to do. Could someone please explain what each one is and what it does? Thanks.

See …
SC4 has real-time preview in Audacity so you can experiment with its controls and instantly hear what effect they have.

The “LevelSpeech” plugin will compress : it only has one control … Missing features - Audacity Support