OK, so I already have Simconnect (hopefully) and I’ve now installed Touch Portal, which does talk to the tablet. Seem the $15 refers to the Pro Upgrade? It’s £12.99 in my money.
The tricky seemed to be the bit in between: the Simconnect plugin. I think the main issue is that you need to upgrade to Pro to use a plugin.
However, after paying, I still need to find a .tpp file. There isn’t one in the MSFSTouchPortalPlugin-master zip [later] found it! A separate thing to download and install. Now I can import the plugin, and it says ‘Plugin imported successful.’ but there is no plug in the settings/plugins list, before or after restarting the program.
Am I looking in the wrong place, or looking for the wrong thing?