Barrack (and dorms) are constructed buildings used by cities and guilds to house their legions and fieldworkers. The barracks typically consists of two locations: a guardroom and an interior halls. The interior is a "protected" location and is where legions are housed when not on active duty - safe from spying eyes - and wherein they may train without revealing skills they learn and to what extent since this is often important private strategy. Barracks interior locations are saferooms so you can do whatever legion-related business in relatively secure surroundings (see HELP SAFEROOMS).
Barracks have a maximum number of men they can accommodate in the interior so most cities and some guilds have numerous barracks dotted about the homeland and often in outerlying strategic points of the sphere of influence (see HELP SPHERE and HELP INFLUENCE). The Barracks guardroom is the location used for enlisting men into city or guild legion banners after collecting them from around the continent and gathering the would-be soldiers in groups ready for assembling (see HELP 21 for the Guide to War and HELP 22 for the Guide to the Battlefield - the two sections covering this facet of the Avalon gamesystem).
NOTE: untrained enlistables assembled in ready groups in the Barrack guardroom become automatically part of a city guard (if this service is active/paid for by the State Ministry). These men - prior to joining a legion banner and beginning specialist training - form the mainstay of the city guards whose job is to engage enemies spotted inside the city walls, responding to the CRY of the needy citizen (see HELP CRYING).