What is the initial phase of a particle, in SHM, starting from an extreme position?

What is meant by phase of a particle executing SHM ?

The potential energy of a particle performing S.H.M. at extreme position is

The kinetic energy of a particle performing S.H.M. at extreme position is

The velocity of a particle performing S.H.M. at extreme position is

If the time period is T then what will be the time taken by a particle executing SHM to traverse from the position of equilibrium to an extremity?

The acceleration of a particle performing S.H.M. at extreme position is