You don't need to know anything about Tarot, or even look at the faces of the cards, to use this technique. Just shuffle the deck and pull out seven cards. But no peeking! Keep them face down.
This is a simple technique that can be used without any knowledge of Tarot whatsoever. Have the querant shuffle the cards and select 7. Then have them lay the cards face down in a pattern. Observation of the way the querant interacts with the cards, as well as the pattern in which they place the cards, give you a lot of information. I will give a few suggestions below but they are not exhaustive. They are just suggestions about how to start thinking about this technique.
Sometimes I use this technique in readings, maybe to finish off, or maybe as a bit of an ice breaker to begin with. When you’re finished, turn the cards over and see what you think. You can also try having the querant ask a question before performing the Hidden Face and interpreting the layout in relation to the question, then turn the cards over and interpret them in much the same way, ie cards close the querant may indicate immediate problems, cards placed away from other cards may indicate a disinclination to deal with them, cards placed far ahead may indicate something the querant wants, a goal etc. It’s a very intuitive technique so don’t worry about what the cards ‘should’ mean.