How do you do them and what do they acheive?

hypnosis simply works by suggestions from a source and submission by individual or group.

We are under constant hypnosis via the media.

If the source is knowledgeable, and sincere, then the outcome can be beneficial to the recipient.

Unfortunately, both media and most hypnotists are charlatans. They flourish by manipulating others.

There is also a certain state of consciousness that elevates the hypnosis. This brain condition can be trained by meditation.

self hypnosis can be achieved.

It follows the same pre-requisites to be beneficial:

1 - The Ego must be sincere;
2 - The Hypnotist must be knowledgable;
3 - The state of consciousness must be there.