Hi and welcome!
Give your guinea pigs time to get their bearings and settle in, but at the same time establish a firm daily routine so they can learn what is expected of them. Hang around the cage and talk to them lots, so they get used to you (even if it is from the safety of a hidey at first); a predator that is making noises is not hunting! Be encouraging and praise your little boys lavishly for every little succes like you would a small dog.
You need to be aware that unlike guinea pigs from a good rescue, shop piggies have had no friendly human contact, so in addition to being separated from their family and mates, they have to deal with a new home and living with huge potential predators - that is a big ask for prey animals!
Guinea pigs will mainly bite in self defense if they are handled very roughly and feel threatened for their lives. If you get them used to your hands bringing nice food and tidying up their cage first, you won't have that problem.
Train them with a little veg treat and a specific call to come into some kind of pickup conveyance (a tunnel, cosy, padded shoebox with one side cut of etc.), so you do not have to chase them around and upset them - while guinea pigs generally don;t mind being held, picking up is cutting too close to comfort for most of them. That may take some time, but it is worth it in terms of winning their trust quicker by stressing them out less!
A few piggies may try to tweak you, often when they need to go back to the cage for a pee, but they can be taught firmly but calmly that this is not the way to catch attention and they will usually stop quickly and find another way to tell you (usually by squirming or in some cases by tugging on your clothing). I have a special "uh uh uh" to express my displeasure and to tell a piggy that something is just not done.
Here are more tips on how to settle nervous new piggies:
http://www.theguineapigforum.co.uk/showthread.php?t=36239
You can learn more about the best way to keep boars in our "boar guide" in the behaviour section; further links in there will also help you to read their behaviour.