One of the first thing a beginning bridge player learns is an opening bid of 1 NT.
Remember the opening bid is made by the first person to have 12 or more points in their hand.
When to open the bidding with 1NT
You should make an opening bid of 1NT when you
a) have 12 – 14 points in your hand (if you are playing Acol bridge) or 15 – 17 points (if you are playing American Standard Bridge) AND
b) you have a balanced hand (no void, no singleton and no more than one doubleton)
A void = no cards in that suit, a doubleton = only two cards in that suit.
What does this bid tell your partner
If your partner opens the bidding with 1NT you know that their hand contains 12 – 14 points for Acol bridge or 15 – 17 points for American Standard bridge and is balanced.
If you hold fewer than 11 points in Acol or 8 points in American Standard then you know that you are unlikely to have the 25 points needed for “game” – unless your own hand contains a short suit or a void and you can count shortage points.