i think he's trying attach an additional hd to an running zentyal system, but don't want to destroy the data/partitions on the hd.
1. power off zentyal, connect your hd.
2. power on and from command line,
$sudo fdisk -l
$sudo blkid (get the UUID's for the new partitions)
you should see your new hd listed.
3. mount the partitions to new file systems
$sudo mkdir /mountpoint1
$sudo mkdir /mountpoint2
4. edit /etc/fstab
UUID=<UUID1> /mountpoint1 vfat defaults,user,exec,uid=1000,gid=100,umask=000 0 0
UUID=<UUID2> /mountpoint2 vfat defaults,user,exec,uid=1000,gid=100,umask=000 0 0
5. mount
$sudo mount -a
someone correct me if anything i missed pls.