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Can someone help me out? Maybe walk me through? .........................
Your description has features that lead towards a couple of very different conditions. Please review each of these initial thoughts and see if any helps.
Possible Start Button Disabled:
You mentioned you were
"able to calibrate it" and
"looking at the controls".
Without knowing what you meant by "calibrate" and what you meant by "controls", this is a speculation. But if the two statements taken together mean you had accessed the "Channel Settings" feature of the ST24, that will probably explain a lot. You can't fix errors that occur there. You can only delete the current model, create a new model, select the new model and bind to the new model under the RC flight mode section of the controller.
Wrong Flight APP selection
You mentioned
"...I even had the motors running and ready for flight.". This implies something changed after that. You also mentioned
"no camera".
Did you select FPV flight mode sometime after the motor start event? The ST24 controller will not bind in the normal FPV flight mode if no camera signal is detected. If the ST24 is in the FPV mode, switch to RC mode, create a new model in the RC Mode, select the new model, and bind to it. When GPS is acquired, the motors should start.
Hardware failure
You mentioned
"looking at the controls it was showing that it wasn't registering anything when I would push the engine startup button." It matters what you mean by "controls".
If the
"Final output monitor" in Channel Settings is what you mean, the problem is likely the issue mentioned above.
If the "B1" button on Hardware Monitor is what you mean, it may be a known hardware problem. It is not common, but the Start Button (B1) has been known to get jammed down on the switch shaft enough that the button itself bottoms out before the switch is activated. Pull the button off, put some very small bit of something in the hole to act as a spacer and put the button back on.
General:
You mentioned both the H920 and the ST24 are new to you. Prior ownership usually does not mean much for the drone, but folks mess up controllers all the time. And them sell them because they don't work right anymore.
It is not worth the effort to try to find all the possible mistakes and correct them one at a time. The overall best approach is to do a factory reset, create a new model, and start all over. You will have to set up the time zones, home WiFi, create a new model, rebind, etc., but none of that takes anywhere near the time and effort as untangling a can of worms.
One final thought to consider:
"Channel Settings" was meant for purposes that do not apply to any drone sold under the Yuneec brand. It is a series of setup tasks used by prior controllers to match a generic controller to a generic RC vehicle. Yuneec kits are already setup as "Bind and Fly" equipment "Bind and Fly" means the dozens of required controller settings and variations have already been adjusted to match the intended vehicle model. There is no need to even use "Channel Settings".
The dozens of settings and variations in "Channel Settings" are a web of human errors waiting to entrap an unsuspecting visitor. Yes, "Channel Settings" could theoretically be used by experienced users to tweak controls a little. The reality is that it has led to way more problems than benefits.
The ST16 version of the controller gave the option to disable "Channel Settings". Unfortunately, I know of no way to disable the feature on ST24. Just bear in mind to stay out of it, and if things ever start acting weird, either create a new model or do another full factory reset.