Question

bought a new hard drive for computer, will be secondary one, what needs to be done to the
drive and what do these 2 tasks do?

Answer 1

You need to mount the drive. This makes the drive physically compatible. Then, you need to format the drive (if it is not pre-formatted)/make sure the OS recognizes the drive. This ensures that the drive functions in harmony with the OS. Don't take my word as law; I'm simply providing my personal answer. Hope it helps!