The template is a guide pattern: if you want to make your own texture you can take it into paintshop and use the lines as a guide to painting new colors or patterns in a new texture for your balloon. Or delete it: its not necesssary. Fun party trick: Try the template as a displacement map, or a blend mask to add color to the base shader.
The .mtl file describes the materials in your model. It can be deleted also. You can edit it in Notepad to change the order in which TG lists the shaders in the object's multishader (this is done before importing the model to TG). When several models share the same named material I edit their mtl files to all use those same textures in the same slot.
