If your cameras are in the Smart Home supported model list, but you can not find the cameras in the Smart Home section, then you need to upgrade the firmware for the camera.
Applies to: All Reolink cameras (Reolink Argus, Reolink Go, Reolink Go PT, Reolink Duo 1 series, cameras paired with the NVR system, IP cameras with old hardware IPC_3816 excluded)
Note: Currently, the cameras can ONLY show Live View on Alexa. Other features are not supported yet.
You can refer to this article to upgrade your camera to the latest firmware: How to Upgrade the Firmware for Reolink Products.
These two articles show how to add cameras to Smart Home: