easy.
1) right after you build it, you will see it :) . You should already have them.
2) stamina is spent on blocking, running, attacking. If it goes away from not doing one of those, something is wrong, do you have mods?
3) iron is in swamp crypts. not all swamps have crypts.
4) stone cutting requires iron.
5) you already have the karve, the medium ship (i prefer it as my go-to ship because it can sail a river)