Help with Texturing

I need help with Texturing a model and saving a image of a texture that I can load into a game that is not made with blender.

you need to use UV mapping

Ok and if I want to make a texture for a shield for example and needed different textures would I have to make a custom texture or could I apply different textures to each face and export the image to be loaded into a game?

You can set up different textures, but you’ll need to combine them into one image if you want to make the best use of the uv image space. Besides, setting different images per face might not look very good depending on the images used.