I need help

So I go on the bus for school and I wanna watch stuff in my iPad so I was looking for offline videos and this app I thought would work so I copy link the video for yt and it doesn’t work it shows this ⚠️ so please tell me what to do to fix that bc I really wanna watch my videos on here please reply or help me I try to watch videos to help me but it’s for tv or something so please help and reply