JCrew formal dress size 8

This is a lovely black Maxi length. formal dress size 8 from j.Crew. I can't for the life of me figure out how the straps work which is why they look so long but I think they are supposed to cross in the back or something. Note that the condition of the hem is a bit frayed and there are some markings. this is a dry clean only dress 100% polyester but it's so silky feeling. selling as is and all sales are final.