Break it down the clean off packaging grease and crud, lubricate it thoroughly as it's unlikely it's been lubed the whole time it's been sitting at the shop, and most importantly inspect it while it's taken apart. You don't have to be an expert and understand what every tiny part does (though you may want to learn that in time). Just make sure everything looks ok, nothing appears cracked or broken, and there's no super-obvious scraping or wear points developing already. If there are, something may be out of spec.
Then go shoot it and dirty it up as much as possible.