I need a tutorial about making textures
 

anybody? (link)

good question.

may I ask what is it that you need to know?

you can find couple programs to make textures. (look on some quake3 sites) or any art program will edit/make texture for you.
just after you edit or create the texture a new .shader file will need to be made for the texture.

I have a tutorial for that on my site Honor Editing