Open a new file with 1024x852 px and 72 dpi. Using the following tool

picture the background which colors’ codes are shown below.

Apply another tool now

and represent a rectangle with the parameters from below.
Blending Options-Gradient Overlay
Gradient’s parameters. 
Using the next instrument

draw the next figure colored in
4ECF24. The sizes are the next ones. Use now the next tool

to delete the lowest part of the picture.
Blending Options-Gradient Overlay
Gradient’s parameters. 
Take again the next tool

and insert the next element of our picture with the sizes from next image. After that, apply

to delete the top part of our picture.
Blending Options-Inner Shadow
Hide exactly this layer now.
Blending Options-Gradient Overlay