To get information about another player's armies and towns, you have to send a scout to their towns. To scout a town, select a hero with no army and click on the town on the world map. Then click the "Scout town" button to open the scouting window. This window lets you set up your scouting type and duration. You can scout heroes and troops, the town itself or the region buildings and mines. You can also adjust the duration of scouting. The more time your hero spends in the town, the more accurate the scouting will be. Also, you should know that an inexperienced hero can be captured if he tries to scout a town protected by a strong hero too quickly.