Any advice on moving out?

I have been secretly saving money and looking for places. I'm really scared on how to bring up the subject with my Nparents. I'm also scared that they would block the doors from physically allowing me to leave the house. It's so stupid I'm 22 and I feel like I should be allowed to leave, even for a little bit. I can't stand living here anymore, especially with quarantine in place. How close to the day should I tell them I'm leaving? And how should I say it?