How to import two Gnucash files from two computers to one computer

[Claire Light]

Hello,

My husband and I switched from Quicken to Gnucash about 6 months ago and we
love it.
We each had our own computers from which to work on our separate personal
accounts, nothing complicated.

We now have only one computer to work from a dual boot Windows 7 and Linux
mint 18...and are cutting the cord from Windows.  I have exported my
Gnucash file successfully to Gnucash on the Linux partition, and his onto
the Windows 7 partition, only because I have not figured out how to import
his file into the same Gnucash program as mine on the Linux partition and
be able to easily switch between the two.

I have read on many occasions that we can have multiple accounts, personal
or business on the same Gnucash program...please excuse my lack of proper
wording and newbiness in expressing myself.  I have seen on a post how to
open a new file,  how to merge two files but have not found anywhere how to
import a second separate Gnucash  file/account, so that we can both work
from the Linux partition, at separate times, on our separate accounts.  I
hope my question is clear.

Would someone be so kind as to direct me on how to do this ?
Thank you in advance,
Claire