Working WIth Primary Sources

My question is How do Scientist, Historians, Archeologist knows how the earth was established or even how long humanlike have been around. There must be for the most part concrete evidences, yes. How can these people established the time and the date as they do for the History of the Universe calendar.  Big Bang January 1st some 13.7 billions years ago. This calendar really took me to another level of How do people know? What type of theories was said on what material they tested for this knowledge. How do they know the time and date too.  I am so blown away by the cosmic calendars. The artifacts that archeologist finds how do they know such dates and the age of them. What type of people and lifestyle they have lived.  This is just amazing.