First have a look over here:
http://www.esoui.com/forums/showthread.php?t=5236
Normally you should be able top copy&paste the files from the OneDrive to your local hard drive, at some folder like c:\games\TESO or whatever you prefer.
If you start the game launcher from c:\games\TESO\... it should find the files in the same folder of the launcher. or yous imply execute the eso.exe file from within the subfolders, to start the game without the launcher.
If you need to change the path of the game somehow because it doesn't work, use the tool Registry editor (windows Key + r to run a file: regedit) and search for "zenimax" or "elder".
If you see a wrong path, backup the entries (manually, screenshot, or export the whole stuff to a .reg file to be able to import it again later on) and change them to your new directory.