After opening the serious editor 3.5 you should see this.



Now let's go search for a model.



And now we've got one.

And how do we export? By that upper-right export fbx button?
Well we have a better format to export but before that change model editor to mesh editor first.


You can see that the options have changed...


Export it to .obj (or fbx, your choice).
I recommend you to export files to SS3 userdata folder, as it's easy to find and not so many files in there.

Exporting mesh gives you mesh, but no textures.
Similar to mesh, change the editor to material editor.


You should see this list at the left side of the editor.



Move cursor over the list to find which one is the texture file.



Right click on the list that shows texture file and export.




Some models use more textures than in the list, or showing the wrong one.
Simply left click and browse for it.


And by that you should get all the textures you need.

Here's a proof that the model is useable.


And that's how we do it on planet Earth, you overgrown space cockroach.