did you make techno before?
just increase ratio, and then decrease threshold, you should notice the output signal getting lower in volume, then turn the gain on as much as you want, attack and threshold aren't that important, you could also use a vocal preset, and if you dont notice anything, decrease threshold, and then compensate the volume loss with the gain knob
in the end you should get a signal with a more constant volume which should fit better in the mix
however, the attack and release parameters are a little bit hard to explain, i recommend you search for some sort of larger more in depth tutorial on how to compress, there are already a lot of good articles
just google, and then read read read, it takes its time, but it's worth it