I had the same problem as described at New Mobile app - first impressions - #12 by jsprince3. I looked at the Add Device Page documentation. I saw the standard Add Device screenshot under Naming a Device. I then expanded the How to Add a Z-Wave LR Device entry which has:
Open the Hubitat mobile app and go to Devices > + (plus icon) > Add SmartStart Devices
I mistakenly put 2+2 together and looked for the Add SmartStart Devices button on the Devices page after connecting to the hub and clicking Devices > + Add device. I didn't click the device tab in the new app. I know this is because the V2 app is new but the difference between accessing things while connected to the hub from the app home page vs. accessing things after clicking Connect to Hub wasn't obvious to me.
Can #2 of the How to Add a Z-Wave LR Device documentation page be more explicit - something like:
Open the Hubitat mobile app. Select the (Devices) tab. Select the + (plus icon). Select Add SmartStart Devices.