Step 1:

Start a new document of size 300x300 px. Create a new layer and draw a rectangle using the rectangular marquee. Draw a circle using the Elipse Tool (u). Hold Shift as you draw to get a perfect circle. Fill it with red colour.

Step 2:

Now right click on this layer and select duplicate layer

and fill the new layer with black. Now use the Magic Wand Tool to select the circle i.e. in black i.e the new duplicated layer. Then press ctrl+t or Edit>Free Transform now we need to adjust the size of the new duplicated layer. To do so change the value as show below

This is what I got after resizing the new layer

Step 3:

Now create a new layer and use the Rectangle tool to draw a vertical rectangle something like this. This layer should be placed on the top of the existing layers. This is what I got now.

Ctrl+click on this new layer and press ctrl+t now use the following options to title the vertical bar by 45*.

This is what I got now

Step 4:

Fill in the background with black colour (create a new layer and bucket fill it with black and pull it down to the bottom most layer. Let me show you how my layers look like now.

This is how my image looks like now

Step 5:

Now press Ctlr+E or Layer>Merge Down to merge top layer with the bottom layer i.e. the top 3 layers. Now we have the symbol as one symbol and the background layer as seperate layer. Use the Magic wand tool to select the Red symbol, then go to Layer>Layer Style>Satin and use the following settings.

That's it we are done. Here is my Final result a 3D Stop symbol.