I often add or remove hard disks or SSDs. Below is what I always do (maybe
insecure, but very easy). For your reference:
1. Connect to hard disk or SSD to your system. Create partition(s) and format
them. Get the UUID.
2. Create mount points (sub-directories) under home directory
(/home/username). I never mount 2nd disk under /media or /mnt, etc.
3. Modify /etc/fstab to add new mount point with the UUID. The parameters are
same as /home partition.
4. Reboot the system. If the mounted directory (e.g. /home/username/harddisk)
is read-only, change the ownership (for only once):
~$ sudo chown username:username harddisk
Hint: try not to use sudo to run GUI programs like pluma. Use a command line
editor like nano with sudo instead. Or else you can try the sudoedit command:
~$ SUDO_EDITOR=pluma sudoedit /etc/fstab
Some GUI text editors (e.g. kate) can't be used with sudo at all. If you try
to run "sudo kate", it won't start.