Since it's not really super obvious how you would do this yourself, I should explain the procedure:
Go to the link I posted
Click on Run in Google Colab
In the left hand side of the screen, there's a files menu. The third folder has a Google Drive symbol, you can click on it and it will open a cell that will allow you to link your Google Drive. You could also upload the files directly, but I was doing a lot of them so I preferred using Drive.
Run all the cells up to the one with this code, and put the path to the files here:
content_path = <the image you're gonna do the style transfer to> style_path = <style image>
Run the rest of the cells until the one with the Fast Style Transfer... header, that's the one that will give you your output.
Since it's not really super obvious how you would do this yourself, I should explain the procedure:
content_path = <the image you're gonna do the style transfer to>
style_path = <style image>