We sold a fairly high dollar (for us) item nearly four days ago

The buyer has just one feedback and has not paid or contacted us yet. I'm going to file a non-paying bidder as soon as it's 96 hours old this evening (that's still a thing right, 4 days after auction ends to start it and another 96 hours to close it?)

So how do I do this?  Never done it before and want to do it right.

I remember reading on the forum about this quite a while ago and the came away with the idea that this is the best way to handle it.    Am very wiliing, however,  to listen to the advice of other, more experienced sellers.Looks like I go thru my ebay sold page and chose report a buyer from drop down on left.  I'm not going to do it until 96 hrs but it does look like I could do it now if I wanted to.