Source: L.A. Times
The timeline based primarily on unnamed "authorities":
On Monday, January 28, Spears' representatives including her psychiatrist began confidentially planning the involuntary hold with the LAPD. The elaborate plan focused on dealing with possible interference from paparazzi and included dozens of officers, road blocks, and helicopters at an estimated cost of $25,000.
On Wednesday, January 30, Spears' family & psychiatrist gathered at her home "to execute their plans to take her in for an evaluation." Several hours before police arrived, the street outside Spears' home was jammed with paparazzi. Police tried waiting out the crowd before taking her in.
On Thursday, January 31, shortly before 1 a.m., LAPD & LAFD entered Spears' property to remove her via ambulance around 1:08 a.m. The ambulance was escorted to UCLA Medical Center by LAPD officers.
LAPD Lt. Rick Wall of a unit that responds to mental health incidents said, "Most go exactly as the one last night, without the 200 paparazzi. We get calls from family members daily who are worried about their loved ones being a danger to themselves or others."
On Friday, February 1, court spokesman Allan Parachini shared that Jamie Spears & Britney Spears' court-appointed attorney were granted a temporary conservatorship over Britney's personal affairs and estate. The court also issued Jamie's requested restraining order against Sam Lutfi.
On Sunday, February 3, an anonymous source close to Spears who was unauthorized to release such information revealed that her involuntary hold would be extended by fourteen days. This 5250 hold was authorized by doctors and a medical officer.
On Wednesday, February 7, Spears was released from the involuntary hold at UCLA Medical Center. Spears was stalked by crowds of paparazzi as she drove herself home, then to a hotel. She had been held under 5150 & 5250 holds, which end when medical staff determine that the patient is no longer a danger to themselves or others. Spear's parents angrily insisted that the hospital violated the court's conservatorship orders to keep her hospitalized, despite conservatorships being a separate legal order from involuntary psychiatric holds.