How To Add A Hdd To My Whs 2011 Box?

I already have a HDD in there and it's close to capacity now. I bought an exact same HDD to add to the storage. As I understand, there's not a way to create a singular storage pool with all my HDDs in it? or am I wrong? Is there a way?

Also, how do I go about adding a new HDD? Do I have to take care of any configs or something?

Thanks