What to do after root? (for xbmc) topic

I[ve rooted my fire tv.
I'm trying to figure out if I;m supposed to install xbmc through side load.
Or if there is a better way since I have root?

I'm a total noob to XMBC and the fire tv.

I'd also like to be able to plug in a media USB HDD I have to watching my local movies.

But I've always messed with android phones, dab commands, and custom roms.

Any guide or direction would be nice, please and thank you.