Rocker cover seals

So I have been getting oil on the top half of my plugs. I ordered new seals hopefully going to attempt to change them in the next week.
Is it straightforward to do? Is there anything I need to look out for..or do anything in particular order.
What sealant would I require if any... Do I need to torque the Rocker cover bolts in a special order?

I also bought fresh new spark plugs

http://www.gtirworkshopmanual.com/default.aspx?v=213
as a general rule with any head work gaskets work from centre outwards going opposite sides ..... anyway click the link ...  

It says in that link install radiator... Do I really need to remove that?
Is that just for the timing chain as the title says

Should I use the liquid gasket on both ends of the normal gasket. If that makes sense

Its because its for timing chain .... but covers rocker cover gasket ..... use sealant on the half moons i would do a light bead on it all .... that way if there is any imperfections it will seal it .... rather than seep through... just my opinion

Yeah but both sides? As in the rocker cover groove itself and then again on the head or gasket

I would do both sides like a said dont cake it on just a bead .... as you dont want it coming off in the engine .... i would do the rocker cover side first then push the gasket into it firmly then do the head side ... but make sure you clean everything thoroughly before you start thats the key mate i normally use a stanley blade around the head to get all the crud off then a rag with abit of cleaner on it then final wipe with abit of kitchen roll to make sure there is no oil or anything on it .... like i said its just the way i do things other people may do it differently or have different opinions ...

Yeah i get you leighton nice one buddy.

What type of sealant should I use do you have a link

I use wurth rtv black seems decent stuff and never had anything leak with it ...

How important is it that I torque the bolts. I don't have a torque wrench...

Or is the sequence more important

Its not hugely important however its not to hard to rip them out of the head by over tightening so i would say be very careful and for the sake of a few quid for a torgue wrench can be had on ebay for well cheap and a great addition to the toolbox ... sequence for doing them up will spreed the gasket evenly so its worth following the link i put up mate