Downloaded voice but no further instruction

Downloaded voice but there is no further instruction (or obvious way) to import the voice.
What am I missing?

Welcome to Synthesizer V - Synthesizer V Studio Unofficial User Manual (synthv.info) by Claire …

On Windows, the User Manual instruction for voice installation does not work for the trial period.
Apparently, to try out the program on trial basis, you have to be sure NOT to download the trial. Instead, to try before you buy, it seems you need to find (not easy) and download the “Basic” version of the product. Then I was able to install a voice.