How does an English word become the third person singular and plural and the present participle And what is vowel

How does an English word become the third person singular and plural and the present participle And what is vowel

I know that the vowel letter is: A, e, I, O, u. if the verb ends with "e", just add "d". 2. For the verb ending with "consonant + Y", first change "Y" to "I" and then add "Ed". 3. For the verb ending with stressed closed syllable and only one consonant at the end, double the consonant, and then add "ed