I am trying to place the legend box using epilog function. I'm unsure where I can specify the coordinated in the sample code to specify the position.
Show[Plotww, Plotxx, Plotyy, Plotzz,
Epilog ->
Inset[Framed[
LineLegend[{Red, Blue, Gray, Green}, {"ww", "xx",
"yy", "zz"}]]]]