You put the files on your SD Card, in a folder that is named after the ID of your version of Smash Bros.
For a USA version of Smash Bros. you put your files in sd:/00050000-10144F00/
Once that is complete, you insert your SD Card into your Wii U.
Using the web browser, navigate to http://loadiine.ovh
and, when asked, select "SDCafiine + Kernel" or something similar. Make sure that you install the correct payload for your system firmware version (5.3.2, 5.4 or 5.5).
The kernel exploit will launch, and when you get returned to the HOME Menu, re-open the browser and navigate to loadiine.ovh again, the next payload will automatically launch, and this time when you get returned to the HOME Menu, launch Smash Bros. and your mods should be there.