Here are some helpful links:
Also, you may want to move on to the latest release. Version 2018.3.3 addresses some security issues:
In short: install Tableau 2018.3.3 on the new machine, take a backup of 2018.1, and restore the backup to 2018.3.3.
Thankyou for the info. When I do the restore do I still use Tabadmin as I now some aspects are different in 2018.3. Do I need to use the noconfig option I have seen mentioned to stop it overwriting the config of the new server?
Tabadmin is replaced by TSM in any version > 2018.1:
It's a bit of change but once you get used to the TSM it isn't that bad. I still miss the simplicity of Tabadmin.
The powershell script in the link above should be a good starting point.