So, I now there's a way to do it, and I've searched the tutorials forum, but when I try to do what they say, It doesn't work. How do I do it? don't ask me what I did, I just want to know simply how to do it, from scratch.

Use a image editing program like Gimp, which is free.Click here to go to the official site.
After making the design of the texture,save it as a .tga file.Then create a folder in 'Custom' and put there the textures you want to see.Make sure it has the correct file name like 'head.tga'.Then to see them ingame, type in the chatbox /lp 1 [insert the name of the folder you created in 'Custom'] to load the textures in the place of Uke.To load them in the place of Tori change the '1' to '0'.Click here to get the templates that may help you making textures.

Be sure to note that it doesn't seem to work unless you wait about a minute or two after putting the .tga's in the custom folder.

Since he is not downloading any textures using the /dl command he doesn't need to wait.