Okay lets get started, here in this guide I'll teach you how to use a custom prop from an external link like say from dropbox or copy.com
To start off, make your prop by clicking on the model tab.
http://prntscr.com/6maxc0After you click the link you should have this show up, a plain PAC orb.
http://prntscr.com/6maxmcAfter that you should go and grab the links that you want to be using, I will provide an example but I will not show you how to actually get this link, thats up to you to find out.
(I might make a guide showing all the steps and shit that you would need to port shit over from other games and upload them to an external site like dropbox.com or copy.com once I get a better comp.)
[Then, once you have your model you will need two links, one for the actual world prop, and the second acts as the texture, or "skin".]
[As an example we will use these two links.]
https://copy.com/QuvVtpavs26gOyTl/Scarf_cover_EDIT2.obj[^^This first link will act as the prop.]
https://copy.com/ZNS87nnreGzrOpfn/shemagh.jpg[^^ this link will act as the skin.]
Take the first link and paste it into the model path.
http://prntscr.com/6may9uYou should wind up with this.
http://prntscr.com/6maymcNow take the second link, and paste it into the "Material" tab in the same model prop.
It should look like this.
http://prntscr.com/6maytaNow all that is left is for you to re-arrange the prop using the arrows and what-not.
In the end it should look something like this.
http://prntscr.com/6maz4q