iWeb domain.sites2 does not open after transferring to another computer

I perused other posts, but still could not get a resolution to my problem....

I followed online instructions to transfer an iWeb file to another Mac computer using Dropbox. The file is Domain.sites2 and seems to be intact on my alternate computer. However, when I attempt to open the file (by clicking on the file name), it opens iWeb, but the site is not there. I don't see how to open an iWeb file after opening the program either. Can anyone help? Thanks.