New box, newbie - Where do i start?

Just received my new box. I am a complete newbie to this. I see there are a few different downloads. i can see a march update in the threads, and two firmwares in the download section.
Do i need to do more than one update ie progressively or will what ever the latest one is be the only one i have to install.
I box is completely new. I just don't want to do anything wrong or unnecessary.

Thank you for any help that will point me in the right direction.