| This article is part of the grammar course.
You may choose to follow it in a structured way, or read each item separately.
Syllables are units of sound, and sometimes of sense. They virtually always contain a vowel; often they start with a consonant, and usually they end with one. Native speakers usually have a good 'feeling' for where syllables begin and end; in a foreign language it is harder to be sure. In English, the large number of silent 'e's at the ends of words, and in other places - can make it hard to decide where syllables begin and end. A good dictionary may help.
If you have to break a word to move from one line to the next, you should break it - and insert a hyphen - between syllables, never inside a syllable. (Note that the hyphen goes at the end of the first line, not at the beginning of the second.)
Syllables can be treated as morphemes (units of word-building, like un-, -ing, and so on); phonemes (units of sound); or semantemes (units of meaning). To use any of these terms is not very helpful to most beginners.