First im saying thank you for your help, i really appreciate your help :=) It worked to flip the normals, and about the baked texture. SHould i do it, i tried to search on the internet. But i didnt get a asnwer, so what is ambient occlusion baked texture? Thanks!
You're very welcome!
It's up to you whether you bake your textures but like I said before, it's more efficient because instead of loading lots of different materials, each with their own set of textures into the sim you can just have one texture file with all the materials on it which saves memory.
So you'd bake all of the colour info for the whole model to one colour (albedo) map, then bake ambient occlusion (shadow information, essentially), roughness and metalness to another and then the normals from each material to a single normal map. It's a bit in-depth, but makes more sense once you've done it a few times.
I couldn't find any MSFS specific info either and I had to work out a lot of it by myself so I'm actually thinking of writing a step by step guide on my blender to MSFS workflow. I'm no expert but hopefully it helps a few people!