Well its quite easy i will explain.
1. When you put cards in Mana zone/Battle zone/Graveyard they will always be face down. You just need to double click them to flip it.
2.About deck making , just make a deck (i hope you know how to make deck) and you can use it whenever you want there is no need to show it to anyone. But yes unless you are a premium member you can't lock your decks so by the time you publish them it will become visible to other players.
3.If you want to know the effect of a card of opponent during the game just click on it once and a new pop up will open showing you its effect. If it does not open then check your pop up settings "Pop-Ups should be allowed for tco" .
If you want to know anyother thing just msg me and i will tell you.
I hope it helped.