I can't get the integration going with HACS. Not sure where the issue is. Installed HACS via the instructions.
Added the integration repo though I can't tell if it sticks.
When I try to open the integration I get an error.
The first few things with HA are confusing, much like JRiver
I'm a bit confused where you're stuck and it's been a long time since I setup HACS, so my memory of all the steps might be rusty. Do you have HACS showing in your sidebar on the left? If not, then step 1 is to get that working correctly. Is this the page you mentioned you followed?
https://hacs.xyz/docs/configuration/basic/When you add a HACS integration, you add the repo in HACS, reboot, then you install the integration in the core HA integration page.
If you do have HACS showing in the sidebar and you're stuck with the JRiver integration, if you click on HACS on the left, you should then see a choice of integrations/ frontend/ add-ons. Under Integrations, you should see any repos that you've added (HACS.png attachment). Every time you load this page, it'll show a bunch of new things, I always hit dismiss to see what I have instead of what's new. If you've just installed the JRiver integration, HACS will give you some red banner that says you need to reboot. Once you've done that, then you should be able to add the intrgration using the main HA integration page (Settings > Devices & Services > Add Integration > JRiver).