Holding [E] inside of the hall will bring up its menu, which contains four options: Change Class to the bottom-right, Storage to the top-right, Research to the top-left, and Buy Migrant to the bottom-left.
To put objects into storage, hold down [F] and the select the item in your backpack that you wish to store inside the boat. This will bring it into your hands where you will then need to hold down [E], and click 'Storage'. To take an object out, hold down [E], and click 'Storage'. Once you see the interface of all the objects, click the object you want to take out.
To reseach, hold down [E] and selct 'Research'. This will bring up a menu, where you than be able to vote for a technology. Voting can be done by clicking on the picture of an object. The object with the most votes will be researched along the tech tree.
In general, there are usually 2-5 halls on a map, but there can be as many as the map creator chooses. On vanilla maps, halls currently start neutral, but you can use the blue/red spawn pixels for already converted halls.