First things first, is the distribution point server (the one hosting CasperShare) currently sharing over SMB or AFP? You have to do that first. Step one is getting a regular old server with a share point called CasperShare. See: https://jamfnation.jamfsoftware.com/article.html?id=325. Where it says "create an account that has read-only permissions", you might consider calling that account casperinstall. For the read/write account, you might use casperadmin. Create those accounts on the server that will be hosting CasperShare. Then create the share called CasperShare and give the permissions as listed in the article I just linked. Share CasperShare over AFP or SMB, depending on your preference. We use OS X servers ( :( ), so tend to use AFP, but that depends on your environment.
When that is done, you now have a server hosting a share (a folder) called CasperShare. Your JSS doesn't know about it, but there is a server sharing files with the sharepoint CasperShare.
You could now tell your JSS about it. Using the web interface, in the settings tab, click either Servers (8.x) or File Distribution Points (9.x) and click to add the server to your JSS's list of available servers. You can follow the Admin Guide here, under Server Infrastructure > File Share Distribution Points > Adding a File Share Distribution Points (ignore the HTTP options for now - and don't select it as your master distribution point yet!).
When that's done, you should be able to open Casper Admin and see the server as a distribution point. You can select it and replicate to it, where the JSS will copy everything from your current master distribution point to it. Gravy. If you don't get this far successfully, serving via HTTP won't work either (you can't replicate via HTTP, so there'd be no way to get files onto the share to share via HTTP*).
Now, with a working AFP or SMB sharepoint, you go to the article you found to enable HTTP. In that article:
Step 1 is simply "turning on" HTTP on the server. When you do that, everything in var/www will/can be shared via HTTP. Problem is, your CasperShare folder will likely not be in var/www. That's what step 2 is about. It just adds your CasperShare folder to var/www without actually moving it there (you don't want it there because you're also sharing over AFP/SMB and hiding your AFP/SMB share in var/www is silly). Step 3 in your article is updating the JSS entry you did above (paragraph 3 of this post) so that the JSS knows you want to share over HTTP when clients are accessing it.
I can elaborate on any point above if you need. I remember learning this. Ugh, but it clicks eventually. It'd be helpful to know which JSS version you're running, though.
Michael
* - not really true, but yeah.