Brand new iphone 12 initial setup up problem. PLEASE HELP!!!!!

I just unboxed my new iphone 12 and was transferring my old iphone data to the new one and once the transfer was complete the iphone 12 went into the update screen (all black screen with the loading bar and the logo) I had to leave the house to go back to college and now it is stuck on the loading screen. I cannot go back to the original wifi spot in which I set it up. PLEASE HELP! and thank you!!!!!