First create a directory to mount the drive to:
mkdir -pv /mnt/disk/old-hdd
then mount the drive
mount -t <the file system on the disk> /dev/sdb /mnt/disk/old-hdd
replace the "<the file system on the disk>" with for example ext3 if its that type of file system.
refer to the mount man pages for valid file system switches
after which you should be able to view the drive in the directory you mounted it to