The infrasonic filter (normally marked subsonic) is designed to filter frequencies below tuning to protect the sub from unloading. It should be set about 5-10Hz below tuning. The low pass filter limits the upper frequencies the sub plays and it should be set at 80Hz. The phase adjustment should be set to 0°. It is sometimes usefull for inverted mounts and shifting the phase can sometimes help correct out of phase sub placements but for the purposes of your skill level, let's just leave it alone.
Regarding the other things mentioned here, you need to close that hole in the box with a terminal cup and all of your power wires should be the same size. For that amp, they should be 1/0. You can look at your wiring like a chain.... if you have a 1000lb capacity length of chain and you out a 100lb capacity link in the middle of it, your entire chain becomes a 100lb capacity chain. With that said, there are some considerations that can be made for short lengths of wire but generally speaking and for sure, if you don't understand the math you should always use wires of the same size.