First find your "worldsplayer" folder. If you don't know where it is, right click the shorcut on your desktop and click "open file location".
Create a new folder either in your worldsplayer folder or somewhere else to keep track of your themes. Inside that folder create 2 new folders, one for the base textures and one for the new interface.
Download and extract the zip to the folder you made for the interface. Back up all the original images to the base textures folder so you can go back anytime you want, make sure to include override.ini.
Copy and paste the files into the "worldsplayer" folder (not any subfolder inside of worldsplayer). If you get an error about duplicate names, make sure you have moved all original textures to the backup file.
