There seems to be TWO Tuya-apps for mobile devices, the “Tuya-smart” and “Smart-Life” apps. For all practical purposes they seem to be identical.
These apps are available both for Android and Ios (Apple mobile). I don´t have any Ios-mobile, so my decriptions are of/for Android. Somebody with Ios devices, is welcome to write to me and advice on the differences to my decriptions.
Go to either Google Play-store or Apple App-store and download and install one of the two Tuya-apps.