Making image exterior and interior

So, I was thinking of making a train and learning coding and making the shapes and the putting certain faces in were i'm gonna put the poles and seats and door-walls 
and stuff but 


idk how to make the images/textures for the train and just wondering if anyone knows how help me make them and code them into my train.

Click the tab at the top of the page that says "college" - that's the BVEWW "college of knowledge" with links to tutorial stuff. There's a train building guide - though it's more to do with assembling the driving cab and getting the various train files together.
The "exterior" - which is what you see with the view cam in the game - is basically object building, same as everything else in the routes. Once you have the basic knowledge of how objects are made (same place for the info) then try looking at some train exterior items and you will probably see how it all goes in place. It's not rocket science, but it can be a steep learning curve. The coding is quite simple to learn,you only need a plain text editor like Notepad.  Making the textures is often where the real skills lie - if you have good Photoshop skills I'd say you're halfway there. Good luck.