Reply to Midi Fighter Pro Help/Discussion

Hi there! i recently received my midi fighter pro cue master! Kinda confused though.. 1. What does the second knob do, for it seems it doesn't do anything!
2. Is the first knob always a filter? I see videos of people working the knobs and it is controlling lfo's and other things.
3. the new sample rejuggle mode is kinda weird i know thats not a question but whats the benefit to it?