Local Files don't work on my phone

[Massacrex]

Hello 

I am Turkish

My English is sloppy. I'm sorry if I said anything wrong.

I read Jacob's article on local files, but I don't understand.

My steps;

1. I turned the song into MP3 from YouTube.

2. Spotify also appears in the local files. I just created a playlist.

3. I added songs.

4. I downloaded it, but it doesn't appear on the phone or in gray.

Thanks in advance, I'm sorry if I wrote something that is wrong or incorrect.

Note: I am using Iphone