Why would you use a rule to turn on the light via Alexa? As suggested above, just use the Alexa Skill (or the Echo App as a second choice if you're in a market where the Skill is not available). This will automatically allow voice control of on/off, level, and (if supported) color with no effort on your part besides adding this device as authorized on the Hubitat side. This is how pretty much everyone does it.
You can use Rule Machine to create motion lighting automations, but it's way overkill. Simple Lighting or Motion Lighting can both handle turning on and off a light based on motion, and because they're smaller apps, they'll probably even do it a bit quicker than RM. If you're trying to learn RM, that's different, but keep in mind it's probably overkill for this job. In any case, the docs contain a basic motion lighting example, and I would recommended reading them before diving in.
