Tasks, accessible through the clipboard on the top left of the screen, are the main tutorial in the game, and reward the player who completes them with various rewards, often culture . Tasks vary, but will often help you in advancing through the game. It is not required to do tasks for anything, although it certainly will help. Early in the game, it is suggested that you complete tasks, as they feed your city with resources .
Tasks will reward you with resources, although some tasks only give certain resources, gold and/or culture. The resource rewards are shared equally among all your settlements. For example, if you have one additional settlement, a task rewarding 100 wood and 100 food will give 75 wood and 80 food to both cities.
Helpful Note: Some tasks can only be completed at your Main Settlement, where other tasks may be completed at either your Main or Satellite Settlements.