Adobe Photoshop Gradient Question

Did you click on your GRADIENT tool (G) and look in the upper left hand corner to see if that gradient show up in the gradient selection window?

If it is:
-- open a new file, the size required...
-- Add the required layers needed
-- Make a rectangle
-- Gradient Tool
-- Select the Gradient in that window on the upper left
-- Sweep gradient across rectangle to your liking
-- Make required Opacity adjustments to match
-- On a lower layer, add solid color

 

Whenever I am given a file with a gradient I run the image through photoshop and apply the "posterize" command to see how it was created to make starting points, directions etc a bit easier to see. Here is your file

 

So the issue would be the 'layer 1', it looks like a clipping mask. You should be able to release the clipping mask and than add a new layer in between them and than reapply the clipping mask to that new layer.

 

Layer 1 is a raster layer. You can't edit a gradient on a raster layer, because it's not live – it's rasterized. If you want to edit a gradient in Photoshop it needs to be on a vector layer or a gradient fill layer. If your gradient is in a raster layer and you want to edit it, you have to recreate the gradient.