In a stellar tidal disruption event (TDE) by a supermassive black hole, the in-falling stellar debris forms a transient accretion disk around the hole. I will talk about the evolution of the disk due to viscous spreading. In particular, we constructed a simple analytical model that comprehensively describes the accretion rate history across different phases of the disk evolution, in the presence of a continuous infall of new debris and the disk wind loss. Accretion rate evolves differently in those phases but usually declines more shallowly than the rate at which new debris mass falls onto the disk, notably the t^-5/3 power law. These have great implications on modelling of TDE flare light curves. I will discuss the application of our results on the recently discovered jetted TDE candidate Swift J1644+57. The fascinating topic of disk precession will also be briefly discussed and applied to Swift J1644+57 which shows numerous dips in the X-ray light curve.