Do casinos usually have staff that will show you how to use the slot machines??

Just ask anyone, even another player. Also, in the hotel rooms there's usually a channel dedicated to "gaming education".

And for table games, dealers and sometimes players will tell you how to play any table game you want to: Black Jack, Paigow, Baccarat, etc. because the dealer's work off tips and it's in their best interest to get on the good side of the player.