Tattoo Smart's brush downloads only work using the "Safari" browser.
If you are using an alternate browser, such as Google Chrome, please close your browser and launch Safari.
Then follow the steps in the installation video that was included with your order.
It is also possible that you have accidentally purchased "Clip Studio Paint" brushes which only work in that program, not Procreate. If this is the case, don't worry, we will update your order with the Procreate version of the set or issue a refund. Just email email@example.com and include your name, order number, and a brief description of the problem.