Mojave on an external drive
I currently have Mojave running on my iMac, I know sometime soon I'll need to move over to Catalina.
I have a small software programme that I need to keep and it will not be updated to work with Catalina.
I have a spare, empty partition of 500gig on an external HDD, can someone please advise the best procedure for installing Mojave on that partition and the correct way of moving over the software I need to keep.
I am not concerned about updating Mojave on the partition as it will not be used to access the internet.