New to Blender, how to add a truck interior and hands on the interior scenes

[1948LJMack]

Hi. I am new to Blender and I haven't used the tool yet, but the way the trucks I see in the game are that for one, you have the exterior and then you have the interior. Like lets say, I want to build a 1952 Diamond T 923 cabover and have it to be used in American Truck Simulator. Also back then, many trucks had manual transmissions. I have seen a few videos but not one made for making a truck for American Truck Simulator. And for those who has used the tool before, maybe some of you can help me out. For the 1952 Diamond T 923 cabover, I want to build the exterior and the interior. As for the transmission, I want it to where when the player is playing via PC, and has the transmission set on "Simple Automatic" that it will trip the transmission indicator to cause the "A" to disappear, thus giving the player the feel that his truck for sure has a manual transmission.