Horse Lead Brass

ok what do these idioms mean?
To build castles in the sky:
To get down to brass tracks:
To put the cart before the horse:
To make the grade:
To turn the other cheek:
Lead som1 down the wrong path:
Birds of a feather:
Pick up the tab:
HA im too smart for u all!! i outsmarted u :p lol but really i dunt know the answers either xD