You have to apply for home quarantine. For home quarantine,you have to be fully vaccinated and have to pass 14days after getting second dose of vaccine and you have to mention a home address which is under your name. Means: any utility bill should be under your name/home contract under your name. Only then you can apply for home quarantine.
No. You can’t stay at your sister’s home. Your sister lives there. And you need a house where you can stay without having any contact with anyone. It’s called quarantine. Only your accompany during travelling can stay with you at that house/room.