Phonics is all about using sounds to read words.
Let’s say that you learn that the letter c makes “kuh” sound.
Next you learn that the letter a makes “ah” sound.
And the letter t makes “tih” sound.
When you read those sounds together… “k-ah-t” you have the word for “cat“.
You just learned to read the word “cat” using phonics. It’s that simple.