We recommend covering the side walls along with the back & top panels.
The only exception is leaving about 2 inches of free space directly behind the woofer hole so the woofer isn't playing directly into the foam layer. If the the norez doesn't cover the woofer hole any, then the extra airspace isn't needed. Same goes for the ports below the woofer.
The floor is optional, but you will need to remove the foam layer so your crossover can be mounted to the floor, and also not block the ports.
We do recommend returning the original stuffing to the speaker. Namely over the crossover and on the back wall, still paying attention to not block the woofer or ports