When you make a bet you want to make sure all the other players know that you are confidence about having the best hand and that you’re willing to bet money on it.
If someone else bets, they may force you to fold. So as a new player it is better for you to bet when you have a premium hand and fold with a weak ones.
Once your skill improves, you will be able to make some adjustments so other players can’t read you so easily.
Bluffing is betting with what you think is the lower hand, hoping to cause some other player to fold a better hand, so you can win the pot at that moment, without further action.
To have a weaker hand is much better than wining a hand with a bluff. In order to perform a successful bluff, you need to be able to read your competitors and know when they are apt to fold if you bluff.
Generally, the best time to bluff is when you are against tight players. This is not an easy skill to have but you will develop it with practice. All the top professionals are skillful at bluffing.