First of all, take the "L1_3dprinting_128x64" folder and place it in the "dolphin" folder via qFlipper like this
After that, download the "manifest.txt" file and add the following text at the end of it:
Name: L1_3dprinting_128x64
Min butthurt: 0
Max butthurt: 14
Min level: 1
Max level: 30
Weight: 5
You can customize the levels at which the animation appears, So re-upload the "manifest.txt" to the dolphin folder in flipper via qFlipper, After all the changes reboot your flipper, to find the animation press the "Ok button" on the flipper until it appears
#Remember!
The "L1_3dprinting_128x64_png" folder is for you compile with the flipper firmware, it contains the .png of each frame, remeber to remove "_png" of the folder name to compile it