Cocohue transitons

Can someone please explain how I get a scene to transition with cocohue ?

I set the scene transition time to 300 seconds, but they always change instantly, I'm very new to habitat so still learning

Is there a user manual to read somewhere?

Some background first: CoCoHue scences are quite different from Hubitat scenes. A CoCoHue scene is basically just a switch and button device to Hubitat--Hubitat doesn't know anything about the bulbs/rooms/zones inside. A Hubitat scene, by contrast, works with bulbs, dimmers, switches, or groups thereof.

From your screenshot above, it appears you are trying to use a CoCoHue scene as a switch device inside a Hubitat scene. This will not work: the Hubitat scene will turn the switch, and turning the switch on activates the Hue scene (either immediately or really however you have it set up on the Hue side, though the official Hue app makes it hard to configure much else). This isn't much different from including a "plain" Hubitat switch inside a Hubitat scene: Hubitat can't transition a switch from on to off over 300 seconds. It's just an instant on (think of a smart plug).

If you want to slowly transition Hue bulbs into a specific state from Hubitat, your best bet would be to use the actual bulb devices (or rooms/zones if they're all the same) in this scene. Hubitat can then transition the lights to the desired hue/saturation or CT and level over the specified period of time. These would then really be Hubitat scenes and not Hue scenes, but it could get you what you want if you want the setup to be done on Hubitat. Alternatively, you could create a Hue scene and make its transition time longer, then activate that scene from Hubitat (which you could really just do from the device itself or a "standard" app without getting Scenes involved at all, unless you have more reasons). Again, however, I don't think the Hue app lets you configure these, so you'd need a third-party app. CoCoHue doesn't let you configure them now, either, though I've thought about adding Hue-scene-editing capabilities to the app at some point down the road, and this is one of those reasons where it might be helpful (because I really can't think of much else when the Hue app would almost always be a better choice!).

I feel like I'm not really explaining the problem above very well, but hopefully it helps! If not, someone else can maybe re-phase what I'm trying to say, or perhaps it is indeed clear for you. But basically, this setup won't work as-is since a Hue scene is just an on/off switch (and button) device to Hubitat.