Eleanorduval Yes the third icon is the objectives list. It provides the objectives that are active so far and a hint on how to complete them. If one of these objectives must be performed immediately before the game can proceed it is shown in the blue box.There is to do list third icon?
In the initial release (and in the next update) all the objectives are/will be mandatory (in a particular order) so that the main plot is coherent. After that you will be able to ignore certain objectives if you do not want to follow that route.