Noah and his family would have tried to carry with them as much know-how as they could, to survive, and restart civilization in the 'new world' for which they were headed. The Bible records that soon after the Flood, mankind built a huge city. This was in the fertile river valley of Mesopotamia, around present-day Iraq. Even evolutionists can't ignore the evidence here, and generally refer to this area as the 'cradle of civilization'. Similar styles of pyramids are found in ancient civilizations all around the world.
Evolutionary historians believe that each culture devised the same style of building independently.
As with any group of people in society today, those that existed at the time of the Tower of Babel would have had a diverse range of skills. Some were builders, some artists, and others farmers. However, when God divided the groups by language, the broad pool of knowledge was divided also. The original groups that became, for example, the civilizations of the Egyptians and Mayans obviously included people skilled in civil engineering, building, and so on, as evidenced by the rapid establishment of their cultures. Other groups would have lacked such knowledge.