How to get music from iPhone onto iPad?

Ok i'm really *** frustrated.yesterday i got the iPad mini and just went on it today and downloaded some apps on it.whenever i buy music on my iPhone i buy it from the iTunes app on the iPhone not go to my computer's iTunes. I tried to get the music from my iPhone onto my iTunes library on my computer but it isn't working. I just can't *** figure it out! Iv spent exactly an hour just trying to do this. Then i tried to get some music onto my iPad but i can't select just a couple songs. Now 127 songs are on my iPad that i don't want on there and i don't want to have to go on my iPad and handselect and delete every single one, and in that 127 songs arent even the ones i want from my iPhone. I really feel like killing a *** right now. Sorry I'm swearing but I'm so frustrated!

Look up on the app store icloud, it will transfer all your music on there.