How to use nextGen plug in and mp3 player question

Hi!
I am new to this and in the process of building my own website. it’s for my photography and I am pretty much all set up.
I have installed and activated the nextgen gallery plug in but have no idea how to use it. How can I upload images to it and how do I present them on my website?

Also I would like to add a mp3 player type thing to my website so that it plays music when you open it. I don’t want the music to restart with every click on each page, I just want it to continue to play. How do i do that?

Thanks ??