Raise First In

One of the first things you'll learn is when you're entering a pot (and no one else has bet), it's almost always correct to raise, rather than limp.

Limping allows the big blind to see the flop for free.  You usually don't want the big blind to see the flop for free.  Bad stuff can happen.

Let's say you have      and you decide to limp, because the big blind likes to 3-bet.  The big blind calls.

The flop comes:  .  You're pretty excited (top pair; decent kicker), and so you bet 1/2 a pot after the big blink checks.  The big blind calls.

The turn is .  Now you have two pairs.  The big blind checks. You make a pot sized bet.  The big blind calls.

The final card is .  The big blind checks, and you make another pot sized bet.  The big blind raises and is all-in.  You scratch your head for a moment and call.

The big blind flips over:  for a full house.  Ugh.  😟😠

Here's what one author says about open limping:

Limping in is terrible. Advanced Concepts in No-Limit Hold'em: A Modern Approach to Poker Analysis

Here's a longer article on the topic:  https://partypokerlive.com/en/news/theory-fundamentals-raise-first-in-part-1