Freewebs serves up the file in your Site Manager named index.htm
You can change your homepage by editing the index.htm file. Remember that the index.htm file is what the browser recognizes as your homepage, so change any file to index.htm and it will become your homepage.
Don't want to upload one file at a time? Soooo sorry, your screwed
You can purchase FTP from the Get Premium section in your Freewebs account.