Remember how we said Hangul was designed to be easy to be learned? Well, similar letters have similar sounds and their shapes are supposed to help you remember the sound. Here are the 5 basic shapes from which Hangul consonants are constructed:
 

How do these letter shapes relate to the pronunciation? Read on…
 

Pay attention to your lips and say "man". Notice how your lips come together when pronouncing "m"? The square shape represents your mouth and letters with this shape are used for sounds where your lips come together. The 4 letters in this group are based on a square shape: 2 are covered in this lesson and 2 more in later lessons.

Letter 1 - mieum (미음)

Sounds like: the "m" in man.
Transliteration: m
 

Letter 2 - bieup (비읍)

Sounds like: read below.
Transliteration: b/p
 

So is it pronounced "b" or a "p"? Along with some other consonants (ㄷ, ㅅ, ㄹ, ㅈ and ㄱ), ㅂ has 2 pronunciations depending on where it is in a word. For now just learn the Word Initial Pronunciation. Pronunciation in other positions will be explained later.

Word Initial Pronunciation: p
Other Pronunciation: p or b (Covered in Basic Consonants Revisited)

As you will learn later in the Tense Consonants and Aspirated Consonants lessons, the letter ㅂ also has 2 other variations.
 

Pay attention to your tongue and say "no". Notice how your tongue touches the top of your mouth? The L-shape represents the tongue touching the upper palate of your mouth. The 5 letters in this group are based on an L shape: 3 are covered in this lesson and 2 more in later lessons.

Letter 1 - nieun (니은)

Sounds like: the "n" in nose.
Transliteration: n