Smart thermostats replacement of old

[Ickleric]

Hi I have a 5 year old combination boiler it doesn’t have a thermostat anywhere, it only has a small electric display next to the boiler for the on and off for the boiler . I have been looking at buying a wireless smart thermostat so I can control the boiler temperature from my phone and Alexa smart speakers. I had a quick look at some of them and most sound like you have to remove the old thermostat and wire the new one to it so you can’t see ould control through your phone. But we don’t have one so can’t. Any idea of how to do it?