Encountered some "issues" while trying this, having to do with the wife's little dog, a can of trash, and what trash does once it's in a dog... yeesh!
Anyway, this is one of the important points:
all of the files are in a directory by themselves, and you double-click, or "run" the "LSH3-EDITION-2015-STARTER.EXE" file, and then just answer the dialogs after that. The installer does the rest. Another important part is choosing the correct folder where your game is installed. You cannot be in a Windows protected folder, such as "Program Files (x86)". You also have to have a 64 bit version of Windows. Instead of posting 20 screen grabs though, I made a little pdf file with them all:
LSH2015Install.pdf
Hope you get it going. I'm off to re-do my WAC install, but update to v5.2! Have fun!