Missing files

Hello! I am trying to run the Dogs vs Cats super-charged! (lesson1-rxt50.py) code but I am getting an error on this line: learn = ConvLearner.pretrained(arch, data, precompute=True, ps=0.5) saying this: FileNotFoundError: [Errno 2] No such file or directory: ‘/home/paperspace/fastai/courses/dl1/fastai/weights/resnext_50_32x4d.pth’
What should I do? I also tried lesson2-image_models.py and I am getting this error: FileNotFoundError: [Errno 2] No such file or directory: ‘data/planet/train-jpg/train_0.jpg’ I am obviously missing quite a lot of files and I am not sure what step I missed. The first cats and dogs lesson worked perfectly fine. How can I download all these other files? Thank you!