Prisma Palette currently only works on photoshop 2015.5 and up.
After purchasing and downloading the .zip file from either gumroad or cube brush to install. Open photoshop and navigate to the script loading option as shown below.
Select the installer.jsx
Once this happens a prompt will show up on screen and take a few seconds and then give a confirmation message. Restart photoshop and you should see the panel show up as shown below.
Assuming everything went to plan, now Prisma Palette should be working!