MQTT and Adafruit IO

I managed to get MQTT working with Adafruit IO but only simple functions like on/off and dim. But I can’t for the life of me figure out how to access the API or set colours. Maybe it isn’t possible with Adafruit? I created a video here: Control WS2812B LED light strip with Adafruit MQTT and WLED - YouTube of what I can do so far. Any tips greatly appreciated!

Use JSON in your message.

The URL requires username/feeds/led5/c but I can only seem to use username/feeds/led5/