I'm with GJE52 about attaching going wrong.
Only one bounding box should be left, that makes bigger to encompass the new parts being attached. Maybe do you have them grouped by mistake before attaching them?
(here parts change colour to green when they are attached, just to make it easier to see)
Once all parts are attached you export your mesh with the plugin.
and from the Listener you got your text to be saved as a .msh file.
For the rest follow ashes advice here:
https://www.sas1946.com/main/index.php/topic,30323.0.htmlyou will need in the same folder as your mesh file, at least a material and a texture, this varies a lot between models, but can be more of course. You have to check what you need.
In your case, you probably will need at least two materials (one for the glass, and one for the rest) but depends of how many you have used in your model for non glass parts, so better check what you got in your mesh file, in [materials] section.
(here for this fast example I only have used one: Gloss1D0o)
Be sure that the materials you use point to your textures editing the texturename section inside .mat file (you can edit them in notepad)
[Layer0]
TextureName skin1o.tga
Probably you will notice after exporting that the smoothing is not what you hoped for, and maybe the lack of shadows. But live that for later and enjoy what you got for now.
you are almost there. keep going!