[Shiralee Honeybun]

I recently took to taking a boulders stone out of previous owners pond. The hole is 15ftby12ftand about 2ft deep. Eventually one side will be decking and other lawn. Not I hope you can help, do I divide the boulders and stones between the ponds or get rid and do I put shingle and how much. I’ve never done landscaping before. If anybody could advise I would be very greatful