Here's a very basic video tutorial on how to make a simple 3-D model in Blender (2.79), add textures and export in Collada format before converting it into a scenery BGL with ModelConverterX (thanks Arno!) and installing in FSX. It's aimed at the enthusiastic newcomer to Blender who wants to start modelling scenery, taking a step-by-step approach. Hopefully, you should be able to shorten the learning curve a little with help from the tutorial - good luck!
Cheers - Dai.
Cheers - Dai.