New Mac User Questions

I'll attempt to provide some thoughts.
1. i can't play music because I am not authorized.
Did you sign in to your apple account in the music app? From the Music app, navigate to the account menu and make sure you are signed in. If so, you might investigate the authorizations within the account menu and see if you can figure out what's going on.
2. I am not able to read pdf attachments using preview.
This is a bit vague. Can you provide more information as to what happens when you open a pdf file?
3. I have an 8tb hard drive that was formatted and filled in windows using xfatwhich I would like to be able to use on the Mac. How can I do this. If I can't what do I do to make my windows data available to me.
Again, a little more information would be helpful. Is this an external hard drive? Do you have the proper cables to connect it to the Mac? If so, what happens when you attach the hard drive to the Mac? At best, you might be able to access documents and multimedia content. You won't be able to access software applications natively on the Mac.
4. Finally, why am I being charged for apps such as Sonos Controler and Drop Box that are free on the IPhone and PC? Thanks and sorry for all the questions.
I have no knowledge of the Sonos app, but I've never paid for the dropbox app on Mac. How are you attempting to obtain the app? I downloaded dropbox from the dropbox website. You typically just sign into the dropbox app with your dropbox account.

Sonos app is free however you need to download from Sonos not the App Store. The app that your seeing in the App Store isn't from Sonos but from another Dev. The Mac App Store is similar to the window store in that you can find some apps but a lot of apps reside outside the store on the web.