Does your Keypad look like the one pictured to the left? Then you're in the right place! You've got the Gen 3 SimpliSafe system. If you purchased a system in 2017 or earlier, you have the Original SimpliSafe. Click here for the article for the Original SimpliSafe. If you're not certain which system you have, you can tell the difference here.
To add a new sensor to an existing system, please see this page.
Congratulations on your new SimpliSafe system! Before installing your sensors, you'll need to install your core devices. Then, follow along with the video below to install your Smoke Detector to your brand new system.