Custom Slider - Based on 4 MQTT payloads?

Good evening.

Last night I managed to hack a sonoff RF bridge and discover remote codes for a LED fire place.

As it stands I have all the payloads for every button press.

I need some advice please as to I would take the 4 payloads which determine 4 brightness settings and convert them into a custom slider?

As it stands I have 4 separate buttons ….