That link doesn’t work, BTW. You should edit it. This one works
I did manage to get to the link and keep in mind that is another newbie trying to find their way. There are a lot of ways to template MQTT completely different than that.
I also have written a color helper custom template that can do color conversions for you, linked it up there and here.
I suggest you add an example of what you are trying to do here in order to get better help from the template experts…