This project is not intented to be viewed on not a 3DS. To install this on a (hacked) 3DS, you need to install the "Scratch Everywhere!" homebrew (I recommend Universal Updater). Download the project and put the .sb3 file in the `3ds/scratch-everywhere` folder on your 3DS's SD card, if the folder doesn't exist then make it. After that, you can open Scratch Everywhere on your 3DS, click on the Hat block button and select your SB3.