She has 4 Phases during the fight.
During Phase 1, Neku will only fight Noise. So focus on fighting her with Beat passing the puck at all times. Keep away from the hole on the bottom left.
On Phase 2, Konishi will be greyed on Neku's screen. She is a bit different from normal noise, that exist on two screen. She only stays on one screen at a time. After one combo from Beat, she will move to Neku. Try using pins with 'Grave Marker' or 'Vortex Saber', keep juggling her and keep her in the air. If she turns grey again, that means shes moved back to Beat.
Phase 3 now. Button mash with Beat, focus on Neku. Neku won't have any pins to fight with. You will see her shadow and you shadow on the ground rotating. If she steps on the end of your shadow, you'll lose HP. However the same goes for her. Just step on the tip of her shadow and chase her around. This is probably one of the easier phase when you know what to do.
Phase 4, theres alot of Konishis on Neku's screen but don't worry about them. Keep running around and you'll find a yellow twinkling spot. Thats where the real Konishi is. Just tap it, and Rhyme will come and attack her. Just keep repeating that, and fighting with Beat and Neku when you find the real one.
Its not really that hard of a fight.