The overmap will be a map containing many "nodes". You can move your avatar, representing your entire force, around the map. You must beat missions in order to progress.
Red Dots = Quest Missions. These will always reveal themselves once you've cleared any connecting Quest Missions.
Green Dots = Towns. Sometimes these were previously Quest Missions until they were cleared.
Blue Dots = Cleared Missions.
Orange Dots = Side Quests. These will only reveal themselves if you have learned of them through finding out about them at a Tavern or through achieving special objectives in a Quest mission. There is a random amount of these each new campaign, sometimes there will be none, sometimes up to 5 or 6.
Large Red Dot = Final mission.
You can go to and click on an already cleared node to search for monsters. This is called a random battle. The search will cost you some gold, and there is no guarantee you will find any monsters. Additionally, every time you get a random battle on an island, it reduces the chances that you'll find any random battles. Once the percentage gets under a certain amount, you will be warned, something like "The locals say that they've seen no sign of monsters in some time."
At towns, you can select Barracks, Tavern, or Shop. However, you can only select ONE of these. Once you select one, you cannot select another one again, and the town will not be interactable again. This creates a tough choice the player has to make between getting new quests, new troops, or new items. It also disables the player from revisiting towns to find every quest, troop, or item that they need. Most islands will have at least two towns, however.
The Barracks will have units of your race, as well as heroes. available for hire. There is a random assortment of them, some having special items and random levels of experience.
The Tavern will be a place to collect gossip and tips about the game and the continent. You can also be given special quests here sometimes.
At the Shop you can buy and sell items.
In the single player, there are several different types of missions.
In Annihilation missions, you simply have to destroy all enemy units on the map. Sometimes these have a timer.
In Objective missions, you have to destroy/claim a specific unit or tile. Sometimes it is a specific unit, like an enemy hero, sometimes it is one or all forts. Sometimes these have a timer.
These are rare, but depend on you simply surviving a certain number of turns.
Random battles have randomly generated maps. These are always Annihilation missions, and they do not have timers.