Step 1
Create a new document sized 600px * 600px, fill the background with black colour. Create a new layer called "Cloud" with around 40% opacity, use the cloud brush you downloaded, and paint some cloud onto it:

Create a new layer called "background light", grab a big soft brush with white colour, and paint as shown below:

As you can see, by doing so you immediately created a nice background to work on.
Step 2
Create a new layer called "floral pattern", use the brush you downloaded, paint a floral pattern onto it:

Apply the following layer blending options to this layer:
Drop Shadow

Bevel and Emboss

and you can see now we created some light and shadow effect for the floral pattern:

Step 3
Now we can add a glowing effect to the floral pattern. To do this, simply duplicate the orginal floral layer once, apply the following Gaussian Blur settings to it:

and you will see a glowing edge appear around the floral pattern:

Step 4
Now let's add some colour to the image. The Color Balance image adjustment layer will do the job. Personally I think it's a quick and easy way to add colour to an image, without having to use brush and the colour picker.
I chose a golden colour mix: (Settings as shown below)



and you will have the following effect:

Please note that there is no need to use the exact same colour as I used, you're free the experiment any colour scheme you prefer.
Step 5
Now let's flatten the image (save a layered copy before you do so). Duplicate the background layer, and apply the following Smart Sharpen filter to it:

As you can, we now have a darkened edge around the floral pattern, also the overall image becomes more crispy and detailed:

Now let's get on with the bokeh creation. We can do this with brush dynamics (F5).
Create a new layer called "bokeh" on top of all previous layers, grab a around brush with 90% hardness, apply the following brush settings to it:
Shape Dynamics

Scattering

Transfer (Other Dynamics)

Tick the Airbrush and Smoothing option:

and you will have the following effect:

Step 6
Duplicate the bokeh layer once, and apply the following Smart Sharpen Filter Settings to the duplicated layer:

Drop the opacity of the duplicated layer to around 80%, you will see now we have a highlighted edge appear around the bokeh:

Note: I personally prefer using Smart Sharpen filter to add the edge, other than using the "Stroke" layer blending option. The former produces a clearer, more detailed result in my opinion.
Create a new layer on top of all previous layer called "highlight", set the layer blending mode to "soft light", and grab a soft white brush, do a few single-clicks around the floral pattern as shown below:

Finally, add a levels adjustment layer on top, with the following settings: (this will alter the contrast and give the image more depth)

Mask on the levels adjustment layer:

and you will have the following final effect:


