Okay kiddo, let me explain about progressive rock and its timeline from 1960 to 1969 in a simple way.
Back in the 1960s, there were a lot of musicians who wanted to try new things with their music. They didn't want to just stick to the same old sounds that everyone was used to. So they started experimenting with different kinds of instruments and new ways of playing them.
This gave rise to a new genre of music called progressive rock. It was called progressive because it was always progressing and changing.
In the early 1960s, a band called The Beatles started experimenting with different sounds and instruments. They started using things like sitars and Indian music in their songs. This inspired other musicians to start doing the same.
In 1967, a band called Pink Floyd released their first album called "The Piper at the Gates of Dawn". This album was very different from anything that had been heard before. It had long instrumental sections and unusual sounds.
Other bands like Yes, Genesis, and King Crimson were also experimenting with different sounds and styles of music. They started using things like synthesizers and odd time signatures in their songs.
By the end of the 1960s, progressive rock had become a popular genre of music. Musicians were still experimenting with new sounds and styles, and the genre continued to evolve.
So, there you have it kiddo, progressive rock started in the 1960s when musicians wanted to try new things with their music. It became popular and evolved into various styles. The Beatles, Pink Floyd, Yes, Genesis, and King Crimson were some of the popular bands of that time.