I can't add my songs in my itunes app as I did with the old version.

Before the update, I could create my own lists and add my mp3 songs in the iTunes.

After the update, I can't add any of my songs in the app.

I don't know what is going. I'm using iphone and mac for like 7-8 years, I have my lists all these years and i don't want to change them.

Can you please help me add the songs I've downloaded as i did before?

Thank you.