Step 1:
Start a new document of size 220×260. Fill it with a background colour as Black #000000.
Step 2:
Create a new layer and select the Rounded rectangle shape and draw a rectangle, like this

Select the layer and choose gradient overlay.

and select the following Gradient Colours.

This is what I got my result as

Step 3:
Now let us try [...]

Step 1.
First of all create a new Photoshop document with a black background. Create a new layer , choose the elliptical marquee tool and and make a circular selection (a). Choose the gradient tool and set it to reflected gradient (b). Set the foreground color to white and the background color to black, and then [...]

The first step is to create your canvas. It can be any size you want you button to be. I’ve picked 200pixels by 100 pixels. Mine, of course, will be rectangular.

In hindsight it would be better to fill the entire canvas with your gradient we are about to create. I don’t no why but I [...]