It can be tricky. A couple things to consider when bringing your own creations over. Make sure you have the plugins download extracted to your Unreal Project directory, you have properly exposed the parameters you wish to use in Substance Designer (within Unreal) and then when you import the SBSAR file, all of the Substance nodes come in. I have a video related to this importing if you care to see → Corrugated Metal & Wooden Sheets Pack - YouTube
Ultimately that rack of settings is the Substance Graph Instance (http://bryanthardwick.com/awful-manish/asset01) there is a section on that.
As for scale, layers and procedurals, these will all be parameters that will more than likely be “exposable” in Substance Designer. Once you find the items you want control over in Unreal, expose them, then make sure you double click in the graphs grey background to bring up the properties of the graph itself. Here you will find a rollout that has all of your exposed parameters. This is where it is useful to name them, drag and drop them in the order you want them to appear, etc etc. Wes does a good job of all of this in their Substance to Unreal series, which is here: http://www.youtube.com/playlist?list=PLB0wXHrWAmCyvb0TsSFb3UunisJHcGcuq
I had to watch some of these a few times as its a lot to remember
Feel free to contact me anytime to get help. Also the Allegorithmic forums are handy for questions and searching previously asked questions.