If you have no instructions regarding how to use the flashcards, here's a very brief summary what Doman recommends:

When you are showing the flashcards, do it in a place and time when there are as few distractions as possible.  The ideal position for your child is facing you.  Sitting in your lap is the next best position.  Choose a time when both you and your child are happy and able to focus.  
 


You need to figure out how many to show your child in a session.  Some children like just one card per set while others are happy to see 20 at a time.  Take your cue from the child.  You want to leave him wanting more when you are done.  If he starts to look bored or looks away while you are showing the flashcards, show him less next time.  If you get to the end of your flashcards, and he’s not eagerly waiting for the next one, then you are showing too many.  
 


When you show your child the flashcards, show them as fast as possible (one card per second or faster). Do not ask your child to repeat the words as this would slow you down and pressure your child.  Be relaxed, enthusiastic, and joyful!  Look at your child while you are saying the words.  When you are done be sure to hug and kiss!  Then shuffle the cards so you’re ready for the next session.
 


It’s important that you never pressure him about reading.  Reading must be completely and totally fun!



If you want a more thorough summary see the group files FAQs in the Yahoo Group Teach Your Baby to Read. And for the ultimate description, read How to Teach Your Baby to Read by Glenn Doman (1995 or later).