How can I create surface based on this 3d sketch frame lines?

Hi,

I'm going to test Solidworks' free-form modeling ability but I couldn't make the surface I want. I think it's a simple work but I'm a newbie and I need some help. I created the frame using 3d sketch but boundary surface tool cannot create a surface using those splines. please guide me. The file below has been saved in SW 2018.

Thanks.

SolidworksDrawings And Detailing