Adding on textures to Stock AC

I new at most of this but I'm trying. I have turned my aircraft files into excel files. I understand how to edit them to match up with the new texture folder. Example B737-400 texture texture.1 texture.4 When I do this I can fly the planes only if I start in the air but none of the systems work. If I start on the ground the planes fall through the runway. Is there a way to fix this?