Help! I don’t know the difference when pronouncing ゆ and じゅ

For context, my main language is Spanish and my second is English.

All this time, I thought I was pronouncing it correctly, but it seems I was under the wrong impression that ゆ and じゅ are pronounced the same. Now, a Japanese friend has come to live with me for a year and they pointed out that I'm pronouncing ゆ wrong, that I am saying じゅ. I tried to say we they are my 友人 (ゆうじん) but apparently I said they are my 獣人 (じゅうじん) 😅.

Does anyone has a video or explanation of how to pronounce them? because to be honest they sound the same to me.

by blaziken2708