This is different from the HADB issue you're experiencing. In HE dashboards, you have to go into the dashboard app and select the devices to share (e.g. "Authorize") for use with the dashboard you create. See the Dashboard docs for help with this particular issue.
Keep in mind that devices must create entities in HA to be imported. Curtain is supported by "Generic Component Window Shade" in HE, but I don't know this is the same for that device. I don't own one of these. Perhaps @philtor can assist.
One way to get things working that are not directly supported by HADB is to instead trigger them via an HA automation by sharing a Hubitat Virtual Switch with HA. Set the virtual switch to turn off after 500ms. This is then configured in HA as the trigger for the HA automation, which then controls the device on HA. For this particular use case, you need to use the HE->HA integration created by @jason0x43.
[Edit] Just looked back at @philtor 's post and this is how he mentioned he is controlling his.
