Tasha's Date and No Dose Route:
1) Get the gender reveal scene: either the first time you try to dose her (you won't actually dose her then), or visit her in the office early in the morning, you need to go to work early to do that
2) After 14 days explore the office between Morning and Late Morning for an event with female characters.
2a) Tasha will ask you on a date when leaving work after step 2, accept the date
3a) Get the random event where Tasha gives you her phone number and wait 7 days until you get the second date to her apartment and select "Accept her offer and follow her home"
3b) Alternatively, in normal play, on October 21 "Get lunch with Tasha", then "Go to Tasha's apartment" (I'm pretty that one is bugged and doesn't unlock the rest of the events at the moment)
4) "Invite Tasha over for the day" on the weekend, during morning or late morning
5) In normal play, you need to wait for Chapter 4, in freeplay, I don't think there is any time constraint. After 3-7 days, get a dream with Tasha and Saya.
6) Have the "Weird Dreams" conversation with Tasha
7) 2 days later during the second dream with Tasha and Saya, select: "I want this to be who I am. I want this to be my future!"