I comment this every time I see the sleek loading screen so that others don't have the same problems I did:
PLEASE READ IF YOU'RE HAVING PROBLEMS INSTALLING THIS
1. Customize it here: garrysmod\addons\sleekLoad2\config.js. More on this will be below.
2. If you're adding music use youtube or ogg files. If the music isn't working and it's a youtube link you might have to convert it to ogg.
3. Get a web host. There are some free ones but my server is hosted on NFO so I was able to put my forums and my loading screen on it
4. Drag all the files into the file manager in the web host
5. Get the link of the index.html that's inside your web host files. Here's where I got confused. When I opened this in my browser all I saw was this: "We are currently playing gamemode at map Retrieving server info... You are now listening to" So I put this in the search bar: full webhost link.com/full name of the folder I saved this in/sleekload2. So it would look something like this: example.com/loadingscreen/sleekLoad2. CASE SENSITIVE. If you don't want it to show the sleekload2 in the url you can just upload all of the files into the folder before it or rename the sleekload2 folder.
6. Go into your server files and go to garrysmod/cfg/server.cfg and post in sv_loadingurl the link from step 5. You might have to add sv_loadingurl = "example.com/loadingscreen/sleekLoad2" at the bottom if your server.cfg file doesn't have that line.
Customizing your loading screen 1. Upload whatever images you want into backgrounds/images and whatever videos you want into backgrounds/videos
2. Then upload your songs in the songs folder
3. IMPORTANT. Whatever you want to add to your loading screen you have to add to the config.js file. There is some in there already so you can follow the format from that. You gotta put the file path though so it looks like this: var l_bgImages = [ "backgrounds/images/10.jpg", "backgrounds/images/11.jpg", "backgrounds/images/12.jpg" ];
4. To remove the sleekload logo in the top left of the loading screen go to images and replace logo.png with your logo. Make sure you rename your image to logo.png though.
And that's basically it, hopefully I didn't miss anything. Sorry if any of this is over simplified or confusing. If you have any questions feel free to message me and I'll do my best to help