It appears that I'm in the same situation as this user (Can I use my old home partition and just format the root partition when installing Ubuntu?). As I've not done anything else besides install UbuntuGnome (using the 'Delete current OS and install' option, I should go back, re-install UbuntuGnome and select the 'Something else' option?
I chose that option on my first attempt to install but I went back to 'Delete current os' when the installer showed that my /home partition would be formatted with the 'Something else'. Apparently I need to manipulate the 'Something else' to NOT format my /home partition? Is there anything else I need to be aware of?
I upgraded from 14.04 to 16.04 a couple of years ago and my /home was recognized automatically, but I've slept since then and don't remember exactly what I did.