The rule is the combination of ぃやゆよ. You should listen carefully to the recording first and master the pronunciation of やゆよ.

If you are self-taught, the ways to learn pronunciation are: first, listen (the most important thing is to listen n times, n times), and second, read the mouth instructions (diagrams, if you can understand them).

Friendly reminder: If you study Standard Day, don't practice pronunciation with that Chinese character (like "Ah, Yiwu, alas"). That's nonsense. Then he will be laughed at by the Japanese.

One word is "listening" and the other word is "practicing"