Biggy

Hi all, First post here o/ A little about me: Used to work in a bike shop at 16 (12 years ago) trails was mostly low frame sized XC bikes as the sport haddnt taken off on its own yet. I rode for a few years, had my bike stolen and then i went to uni, had no time or bike to ride... Bought a new XC a year ago and got my fitness back up, about 6 months ago started getting back into trails fun and so saved up for a trails specific bike, somthing i could never afford at the time even if it DID exist at the time lol So anyways, i just placed an order for a bike online and suddenly it hit me, "How the hell with this come to my door". I left for uni when hydrahics and disks were coming out on the top end stuff and have very little experience with them, so im left wondering how much assembly is going to be needed on my new bike. Im not shy of the spanner or a little oil by any means, but will i need specilast tools or anything?! Oh and also, any reccomendations for a new helmet, my current ones taken too many kicks and needs a replacement, somthing light and not sweaty preferably Thanks very much in advance!! Biggy