You can access the Overworld Screen by clicking on the Center Tile on the Main Screen.
In order to access the markets in the surrounding areas and trade for goods and profit you'll need access to the nearby towns. These three towns, like the tiles on the main screen, are randomized each game. One road is always patrolled by the Romans, and for the purposes of the demo the access to this road will always be available to you as there is no way to anger or attack the Romans yet, not that you would want to this early on.
As for the other two roads, you will find bandits or one of the three factions barring your path. To open the road, you'll need to either pay them off or fight them off! The bribe cost is generally highest with Bandits and lowest with the Gauls. Paying a bribe will only allow you access for one month, so make it count. Click on the road itself to bring up the Info and Parley buttons. Info will let you see what troops they have, and Parley will give you a chance to bribe them. Fighting will be covered a bit later on. With a clear road you'll have free access to the markets, forums, and quests, which can offer experience and material rewards. You can also sneak around patrols, a risky but rewarding activity usually performed by Agents, as they have the knack for it.
On this screen you have 2 additional action categories, Combat and Espionage, and a third button, Quests, which organizes all available action quests (i.e. quests you must spend an entire month doing) in one place for you.
Patrol: Only available when there is a cleared (i.e. open) road. Your chosen character spends a minor Combat action patrolling the road, extracting tolls from passersby if possible. A good use for combat characters if you don't have any battles to fight.
Train: Only available if you have built a training yard in your villa, and unavailable during blizzards and subzero weather (as the entire screen is). The character will spend a minor Combat action but gain 2 Combat XP (rather than the usual 1 gained by other minor actions). A handy action, instrumental in getting a Farmhand promoted to a Fighter or racking up extra XP if there's nothing better to do.
Attack: You can execute one attack per month, and attacks come in two types, Raid, and Assault. Attacks do not consume any actions as such, since the actual time consumed by combat is a few violent minutes, but injured characters may not be able to work, so it makes sense to perform your attack after all your characters have taken their turns.
-Raid: A raid is a speedy attack designed to inflict damage and get out quickly. This is a good way to wear down tougher enemies, and with a lucky kill you may even cause them to rout and flee the battle. The formations available during raids emphasize initiative, missile attacks and missile defense. Combat lasts 3 rounds, with a choice to flee after each round, which always succeeds. Fleeing after the third round is automatic.
-Assault: An assault is an all-out attack, with the aim of delivering a decisive blow and scattering your foes to the four winds. This is a good choice when you know you have an advantage. Assault formations emphasize melee attacks and defense. You may not flee until the end of Round 3, and even then fleeing is not guaranteed to succeed.
Combat will be discussed fully a bit further down the page.
Smuggle Goods: A major Espionage action, wherein you sneak a limited number of goods past a blocked road, at a significant risk. Mules can be brought along to add more smuggling space, but also increases the difficulty if more bulk goods are brought. Two separate rolls are made, one to reach the town and one to return, and you will unload your goods at the market and have the chance to purchase in the interim. Failed rolls include the loss of your goods (mules are not at risk) or imprisonment, which can be devastating to your efficiency.
Gather Info: A minor Espionage action, your chosen character will sneak past a blocked road and attempt to create a contact network in a town of your choice that will funnel useful information to your farm for a few months. Failure indicates the guards harassed you too much to be effective, wasting the action (you still gain 1 Espionage XP). Success will establish the network, and a critical success will establish a much longer-lasting network. You may also occasionally steal something at an opportune moment, such as food from a stall or gold, or even uncover the location of the town's Black Market, which sells illicit goods at a tax-free rate and provides an additional black market demand, as well as boosting the income from your sales. The network allows you to view the market and forum without having the road open, and tracks the comings and goings of visitors. This is great for finding out market demands.
Day-labor type quests offered by towns are usually collected here, as well as passive quests given by residents and visitors that require you to fulfill a certain condition, such as providing goods. Action quests can only be performed by a character that has done nothing else that month, but consequently have a monetary reward as well as more XP than could be gained doing ordinary actions. The game will inform you with a message when one of these quests is available, and at which town. The road to a town must be open if you want to accept an action quest at that town. Quests are a great way to train up Farmhands to a specific class, as there is one for each of the basic domestic action types.