Possibly the best example of how hypnosis works to influence people is to look at how advertising works. Essentially, by careful use of words, phrases and images, they are able to persuade people to buy their product and even for them to develop values and positive beliefs about it.
However, is it just a case of putting someone in a trance and then telling them to things in order to control them? Sometimes yes, but mostly this is just the movies. But that said, look at the echo chambers created by social media companies such as Facebook which is able to influence people on a massive scale.
There are lots of books on hypnosis, and masses of varying quality videos on youtube which will teach you a lot more on how it all works.