Below are a couple of questions and answers for each one. If your still stuck just add me on steam.
Q. How do I add this to my server?
A. First you need to configure the loading screen. There are some detailed instructions on the instructions page. If you need help setting your sv_loadingurl then this wiki article may help: http://wiki.garrysmod.com/page/Loading_URL
MAKE SURE YOU ADD ?steamid=%s TO THE END OF THE URL OR ELSE IT WILL NOT WORK!!!
Q. How do I add Music?
A. This too is answered on the instructions page.
Please note that using Copyrighted Songs is illegal as you will be hosting and redistributing the song to everyone who connects to your server. You will be held fully liable for any damages caused to the Copyright Holder.
Q. How do i change the colour of the bars?
A. The colour of the bars have been seperated from the main style shoot so as to make it easier for you to edit. To change the colour of the bars simply open up Colour.css and have a little snoop, all you need to do is change the background-colour to whatever you want. I've used the RGBA colour system which means Red, Green, Blue and Alpha
Q. There are too many backgrounds D:
A. Don't worry, background are dynamically handled based on whatever is in the backgrounds folder, simply add as many or as little backgrounds as you want.
Q. Help I Can't add extra backgrounds D:
A. Adding extra backgrounds is fairly easy, just add another image into your backgrounds folder.
Q. The Loading Bar and Percentage Doesn't Show D:
A. Ok that one can be a bit problematic, Garry's Mod can sometimes be a bit dodgy when telling the loading screen how many files the players needs and this in turn messes up the loading bar and percentage system. I am actively trying to find a solution to this issue but it seems to be with how Garry's Mod sends the file info to us.