Archaeology is very important source to reconstruct the past
Answers
I am no archaeologist, however, I have been studying the Maya civilzation in southeast Mexico and Guatemala and other areas. To reconstruct thier ancient civilization (from pre BC to about 800 AD, the archaeologist use many methods. They first find obvious evidence of the existence of the people by finding pyramidst covered by the jungle and then take years to uncover the jungle growth. They find and study everything and many times, they find stellas (tall carved rock that was put up describing the history of a certain ruler. (the maya code was broken less than 20 years ago). This gives them names and dates and the great deeds of the rulers. It also recites the many wars and battles along with some religious information. Also they discover actual offerings, tumbes with royal leaders and many ceramics along with beads made of Jade and other stones. This alone gives them many clues and they determine the origin of the beads and other obviously imported goods. All this in the basics of determining the culture and even the dates of the site and its importance of the region and the history of the people. Offerings paintings and even sites of worship, homes, work areas, wall built around the cities and even the location of cenotes (entrances to undergound water and the objects found in there from offerings to the underworld.
Many thing such as these give the archaeologist the information they need to determine much of a civilization. The standard technics are used all over the world and they all give us the histories and the advancement of people.
My attention is pretty much strictly MAYA, however I have also much interest in Azted and Inca. Perhaps you might be interested too. You can travel to Mexico to the Yucatan area and see the wonderous ruing of this great civilization. 1 1/2 hours fiigh from Miami to Meride (a great colonial 500 year old city) can be your base for seeing dozens of ruin sites. Further afield in different Mexican states are hundreds of known ruine sites and then also in Guatemala, Belize and Honduras. More ruins are being found all the time, and just recently more sites and cities have been found buried deep in the Peten Jungle of northern Guatemala. I hope to be able to return there and see more of the ruins, some of which date back to 400 BC or so. Happy ruins hunting and I hope that this helps to answer your question.