Cant build mine? And where are the crossbows?

[Samurai Waki]

Easy Answer Mate

Iron is not a mineable resource. It is used Weapons upgrades on your troops. Each Level of metalsmith adds +1 to your units Weapons, making them FAR more effective in Battle.

Crossbows won't appear until the High Era, so if you start out in Early you won't be able to train Crossbow men until you reach 1220 or so.