In Great Britain, the Bronze Age was from around 2100 to 750BC, so it started from around 4000 years ago.
This is when people started making bronze, which is an alloy of copper and tin. It was also the age when people started writing for the first time.
The Bronze Age happened at different times in other parts of the world due to people developing different technologies at different times.
For a video explanation please see below:
The video below shows in detail how they would have made an axe head in the Bronze Age.
For a slightly longer video which is specifically about the Bronze Age in Great Britain, please see below:
If you would like to visit some Bronze Age sites, please see the link below:
A list of English Heritage sites.
Great Orme Bronze Age Copper Mines in North Wales.