You can do it on a different networked machine if you want - that is what I did.
Install WD on the other machine, and set it up as the “client” - also set up you main machine as the “server”. Then it is easy to just copy over the files you want to.
Or, as Windy says, you can do it all on the same machine.
See the FAQ
http://discourse.weather-watch.com/t/10889
I feel the same way - don’t want to break anything!