Livery onto 3D object

Hello All.
I have a 3D object that I need to texture and add some “stickers” too.
I’m an absolute beginner, so can anyone point me in the right direction?
I basically want to add a livery to a 3D object and render it.

Thanks for the help.
MB go down to texture and UV unwrap. for the base texture
Then go here for the stencil

Here is a nice flexible and fast way of applying decals