what realms are you playing in ?
in v4 realms, on the bottom left of your screen, you'll have a small icon showing which version of the game you are playing in. Click on it and you'll have a basic summary of the rules, including storage capacity for evry fort levels
in v4a realms, go to the bottom of th screen and click on "game rules" (there is also a "how to play" with most info you need to play) ...
Finally, when you go to Buildings, click on the picture or the name of the building you want to upgrade, and you'll have a description of its effects and limitations on your kingdom
Have fun,
