You need the Deco smartphone app, and you also need to create a TP Link ID.
https://www.tp-link.com/uk/home-networking/deco/deco-x60/#tp-deco-app
https://play.google.com/store/apps/details?id=com.tplink.tpm5&hl=en&gl=US
Or
https://apps.apple.com/us/app/tp-link-deco/id1186159417
I have a Deco, and they are really easy to setup via the app, but you need to follow all of the steps, and it can take a while for the LEDs to change colour as it has to communicate with the app, via the Cloud server.