The data folder contains the .bin file, which is a raw file will 100 000+ sketches in vector format. bin-file-to-raster.ipynb will make that into an hdf5 of 28x28 bitmaps, but it will be several GB. I never used this approach.
The easier option is to download the .npy files (not included here because of Github's file size limits) directly from Google.
The rest should be self explanatory, but I haven't worked with this code in a while. Shout if something makes no sense!