I need a detailed note on the structure of English syllables.

To answer this question, we should first establish what constitutes a syllable. A syllable is generally described as a “building block” of language, a slightly unscientific explanation that can lead to confusion with morphemes (the smallest possible grammatical unit of language) and phonemes (the smallest elements of sound that distinguish words from each other). Children learn that a syllable is a “beat”: words can contain one or multiple syllables. For example, “printing” contains two: “print” and “ing.” Not all syllables are created equal, as becomes obvious from a study of their structure in English.
Syllables in English are broken down in linguistics into two key parts: the onset and the rhyme. Within the "rhyme" section, we see two further subsections: the nucleus and the coda.
Effectively, the "onset" of any syllable consists of the consonant or consonants that come before the "rhyme." The "nucleus" of the rhyme is almost always a vowel, except when a consonant expresses a vowel, as /y/ does in "Flynn." The “coda” is anything following the vowel.
Returning to “print”, we find all the elements of a syllable: “pr” is the onset, “i” is the nucleus, and “nt” is the coda. “Ing,” however, only has the rhyme and does not have an onset. Syllables like “be” have an onset and nucleus without a coda. “A” or “I” have only a nucleus.