Bidding to game
If you and your partner have 25 points between your two hands then you'll have a fair chance of making game.
Keep in mind that 25 points doesn't guarantee you'll make your game but the bonus points for making game make it worth taking the risk.
Choosing which game to bid
3NT - Everyone's fvaourite contract
If you do have enough points to bid game then 3NT will often be your best contract because you only need to win 9 tricks.
North opened the bidding showing 12 points, South has 13. That's 25!
4♥, 4♠ - Game in a major
Hearts and spades are called the major suits. If your bidding tells you that you and your partner have 8 hearts or 8 spades between your two hands then 4♥ or 4♠ is probably the way to go. 8 cards in a suit is called a 'fit'. You'll need to win 10 tricks to make 4♥ or 4♠ but the trump fit will often be worth an extra trick or two.
North and South have a trump fit.
5♣, 5♦ - Game in a minor
Clubs and diamonds are called the minor suits. 5♣ and 5♦ need 11 tricks.
Hmmm, might be better to try 3NT.