A .zip file is how your files will initially be downloaded. This is a packaged file that includes all the files and assets for the assembly in one download. Most computers will automatically ‘unzip’ the folder and allow you to access what’s inside. On some PCs however you might need a specific programme like WinZip. If in doubt speak to your school’s IT support and they should be able to advise you.
Some computers will not open files from directly inside an unzipped folder. If you are experiencing trouble, you might need to drag and drop the files onto your desktop or somewhere else on your computer.