User:2607:F140:400:A017:5D8B:8A10:E315:9640/sandbox

Hi! I guess this is my sandbox. Why is there no text here? I've submitted links to either my Talk or my Sandbox page before, and there was definitely content in there. I also don't know why it's called User:2607 blah blah blah. I don't know how to change the user page name...