I have no idea how to do any route other than Alice. Is there some kind of walkthrough? I beat Alice but I have no idea how to hand in her report. I went to the library and there's a PC there for handing in reports but it doesn't work. I can't find anything in the starter room to turn in a report?
You turn in reports at the PC of the disciplinary office (where the blue haired rival girl is alongside yourself, at the start of the game) not the library. Make sure you report to the quest requestor after each win, or else a report won't be made (for Alice, the bartender was the one to ask you to get rid of her, so talk to him). The report system is sort of wacky though. Might not be meant to be used yet, since I entered only my first report and despite the competition being about sending 3 reports minimum, after shaking off the temptations of the rival (she tries to get you to give the report to her in exchange for a grope), the game immediately declared me the winner and ended the game.
As for the other two girls beyond Alice you can start their routes as follows:
For Hanabi, there's a bull man running in front of the town center, panicked. Talk to him to get the quest on stopping some delinquents from using some sort of demon drug. Going to the far top right of the town map should show Hanabi (the white haired girl) standing there, having already beat the delinquents. Fight her to either release them into your custody by winning or lose to her enough to trigger her routes. You know you triggered the start of her routes when you are introduced to her sadist and mom gauges. Lose and be an obedient guy to get mom gauge up or lose and be stubborn to raise her sadism. Either way after you win or you lose enough the delinquents would still be freed, and you report to the bullman that the issue is taken care of.
The fungus girl was much more hidden for no good reason. You hear from Hanabi's defeated delinquents that they got the drug from a succubus in the red light district - but you won't find her there (maybe she'll be added later?). Instead, if you head to that district and you'll find a classmate that will give you a quest to search the sewers for missing people. Go down and fight fungus girl to victory or defeat. Get defeated enough and she'll infect you with her spores to take control of your body. The classmate (and the sewer entrance) are both inside an alleyway. There's multiple little alleyways in this red district - but only one actually takes you to the back area, while the rest are dead ends.