Ah, I see you have ended up with the packagetool making a bgl. You need to define your model as a simobject in the PackageSources before building the scenery, so that it becomes a simobject instead of scenery.
So just to stop some potential confusion, the following is a quick how-to, just incase something went wrong when you tried to make it:
Go to the sample Jetway in the SDK sample folder for reference; and you'll want an identical folder structure from the SimObjects folder in your own project's PackageSources folder before building. (Ignore the data folder).
PackageSources\SimObjects\Landmarks\MyCompany_Jetway
with a model, soundai, and texture folder, and a sim.cfg.
"MyCompany_Jetway" can be replaced with your jetway name, just make sure to update the sim.cfg.
Make sure the animations defined in the (your jetway's model name).xml in the model folder is correct like before.
Your model should be a .gtlf and .bin in that folder with the same name as the .xml.
The model.cfg should point to the correct .xml name.
Make sure you have the following Asset Group in the PackageDefinitions folder.
<AssetGroup Name="MyCompany_Jetway">
<Type>SimObject</Type>
<Flags>
<FSXCompatibility>false</FSXCompatibility>
</Flags>
<AssetDir>PackageSources\SimObjects\Landmarks\MyCompany_Jetway\</AssetDir>
<OutputDir>SimObjects\Landmarks\MyCompany_Jetway\</OutputDir>
</AssetGroup>
Where 3 instances of "MyCompany_Jetway" is replaced by whatever you called it before.
If you build the scenery with that, then the Jetway should show up in your package as a SimObject. The fspackagetool will point out mistakes.
If done correctly, you should end up with this in the final package:
Where all the .xml files are in the model folder still, and the model retains it's form as a .gltf and a .bin.
If that works, boot up the sim and devmode's scenery editor and add the Jetway to a gate by clicking on the gate in the scenery window, then add an object type "Jetway" from the objects window, and select your model by name to add.
Just FYI, I'm not an expert either; I just got mine working this way only a week ago. I really hope this works for you!