Whatever level your feasting hall is is the amount of heroes you can have.
Should read SPARE. Upgrade your feasting hall and/or Inn to accomodate 1 or more heroes.
Goto your feasting hall and click one click change
Reinforce 1 troop to the new city with the new hero and build a feasting hall then put it as major
Get an Inn and Feasting Hall built, You can recruit the hero in Inn and he will be available from the feasting hall. Alternatively if you have a Leather Helm of Robinhood from the amulet then you can apply that to get a hero. Make sure your hero has at least one of the attributes high - preferably politics or attack in early stages (>50 min)
You go in feasting hall and you click on appoint mayor. Then you choose the hero you want as a mayor, he should have high points in politics since it affects both production and construction time.
you can't do this
it is the level of your town hall
In the absence of an exact calculation formula, the most relevant method of testing this is by entering the town hall, production tab and recording the "hero bonus" for each resource. Once this is established, enter the Feasting Hall and select "Appoint Mayor" to change the mayor to a different "politics" skill point hero and then return to the town hall production tab and compare the bonus.
When you attack a flat or vally (lake,hill,desert etc.) you have to appoint a hero to attack and to have a hero you must have 1 Feasting Hall (to hold your heros) 1 Inn (to recruit new hero's) then when you attack there should be a drop box and find the hero to lead the attack and press send
all you gotta do is upgrade youre town hall
You can capture a hero several ways. First and most likely is someone attacks you (probably a scout bomb) and loses. When you win the attack if you have a vacancy in your feasting hall you have the potential to capture the attacking hero. Another way is the capture a city. When you do you sometimes capture the heroes that are in that city. Check in the feasting hall to see what you have captured. Also remember to check medic camp to get the troops out. You can also capture heroes that are defending valleys or npcs if you capture them. I have been told that you can also (but seldom) capture a hero from a failed scout however I have never seen the actually happen.