Welcome to the flower arrangement tutorial. I don't know how well I am at tutorials, but thought I would give it a shot.
This tutorial is going to take one image of flowers and turn it into an arrangement of sorts. 
Okay, so lets get started shall we? 

I found that it is best to use a picture that has a bunch of flowers,
but you can play around and see what you like.
Here is the image that I used.

You will want to open a new blank image.
The size depends on the size of your flower image.
To find out the size of your image you can go to view, image information.

Now make your new blank image twice the width and twice the height of your flower image.
My image was 150 x 98, so my blank image is 300 x 196. 
I have mine set at transparent and 16 mil.

The first thing we do is go back to your flower image and copy it. 
Now go over to your blank image and paste it as a new layer.

Now using your mover tool

Move your new layer to the top left corner.

Now copy and paste another layer. 
This time I want you to go to Image, Mirror this layer.

Now with your mover tool, move this layer to the top right corner. 
Make sure they line up real nice.

Copy and paste another new layer.
With this layer you are going to go to Image, Flip.

Move this layer down into the left bottom corner. 
Making sure it lines up nice.

Copy and paste another new layer, this time you will want to mirror and flip this layer. 
Using your mover tool, move this layer to the right bottom corner. 
Your image should look like this.

Now you can merge all layers.

You can stop here or you may wish to add a frame to it.
Proceed to the next page for adding the frame.