Hi Nasser!

1. Please copy "sky_fu_256+6.tga"(install_folder/template/images) in you project folder.
2. Open you main script(main.cpp for example), and add this code

ent_createlayer(filename, flags, layer);

for example:
ent_createlayer("sky_fu_256+6.tga", SKY | CUBE | VISIBLE, 1);