/j/ is the voiced consonant sound.
To make this sound, begin with the sound /iː/ and move your tongue quickly to make the next sound.
Don't touch the roof of your mouth with your tongue.
It's pronounced /j/...../j/.

She is a young university student.
/ʃiː ɪz ə jʌŋ ˌjuːnɪˈvɜːrsəti ˈstuːdnt/
I’m waiting in the queue for an interview.
/aɪm ˈweɪtɪŋ ɪn ðə kjuː ˈfər ən ˈɪntərvjuː/
May I use your iron?
/meɪ aɪ juːz jər ˈaɪərn/
Yes, you may use it any time.
/jes juː meɪ juːz ɪt ˈeni taɪm/
He’s a popular hockey player this year.
/hiz ə ˈpɑːpjələr hɑːki ˈpleɪər ðɪs jɪər/