Styles Just download and unzip the files. See the readme.txt . To preview the new styles, run FontTwister. Click File browser on File menu. Then click a previewed style to open it.
Textures Just download and unzip the files into a new folder.
Then check the Advanced Options on View menu. Click the Surface tab. Then click the Texture button. On the left beside the Texture list you can see 2 buttons now. Classic or extreme - here you find some nice textures.