Here you will specify the path to the existing website archive:

The most common scenario is creating the website archive copy and downloading it to a local machine. In this case, select to upload the file from the local disk.
Otherwise, you might leave the archive file at the remote server. In this case, you can download it directly from the remote location (select Download from remote server).
The last two options apply if you have already uploaded the archive file to your new website manually.