How did the colonists start a fire for cooking?

Well, matches were not in production yet. The easiest way would be flint and iron, which would cause a spark. Aim for the spark to land on some dry tender (something that burns easy like lint, dried moss or leaves). Once it is smoldering blow gently until one has a small flame. Now add wood shavings (pitch pine works great) and increase the size of you small fire. Now add small twigs then larger pieces of wood. The other way would be with friction, a drill and a bow, "Rubbing two sticks together". The bow turns the drill which is placed on a piece of dry wood. The turning drill causes heat on the dry wood until it begins to smolder. Gently blowing gives it more oxygen as one places tender near the hot spot until it reaches flash point and begins to burn. It works but it is work! Another way is with the use of a fire starter. Kind of like a flint lock pistol. Flint and iron cause a spark on a small amount of gunpowder and lights some tender.