Enjoy it
My advice would be to enjoy it and play around with it, it's fairly intuitive not too different from windows and fun to use.
There are endless tutorials online for specific uses so make use of them.
Downlaod VLC for movie playback.
Skim for reading PDF's
Transmission for torrents
Avoid chrome web browser it doesn't play nice with macs.
Other than that play with it until you get it set up as you like there are as many ways to use it as there are owners....