I don't understand what you mean by "In all my programs there is an UltraChannel folder, but there is nothing in it."
Are you able to load the plug-in in a DAW besides Studio One?
Also, are you on Mac or Windows? If you're on Windows, when you run the plug-in installer it will ask you which directory you want to use to install your plug-in. You need to choose the directory that you use for your other VST plug-ins, and install either the 64 or 32 bit plug-in depending on which you need for Studio One.