First: open the picture you want to use as your background. (if necessary, crop it and make it the right size)

Now, open the texture you want to use as your first layer. You can either resize the texture if it’s too big (resize: go to ‘image’ > ‘image size’ and select the amount of pixels), or select only the part you want to use.
Example:

Use the basics of duplicating as explained in the previous tutorial: go to ‘image’ > ‘duplicate’. Adapt the settings for ‘gradient’: go to ‘filter’ > ‘color’ > ‘gradient’. (Color 1 should be black: select 100%. Color 2 should be white: again, select 100%) If it turns out while blending that the background is no longer visible due to the texture, select other settings for opacity, like 75%. Click Ok.
Adapt the amount of noise: ‘filter’ > ‘noise’ > ‘add noise’. The amount of noise should be 5: select the ‘uniform’ square. Copy the second layer.
Now go to the first layer you’ve chosen, and click ‘edit’ > ‘paste special’ > ‘assemble’. (assemble the clipboard data to the right) The black/white and first layer are now one picture: copy the result.
Go back to the background (the first picture you’ve chosen) and click: ‘image’ > ‘paste special’ > ‘paste with linked mask’.

If you want, you can move the layer within the borders of the background.
Now you might need to remove some of the textured layer, as it will cover your background. Use the ‘erase’ tool to do this, in the menu on your right.

Make sure you’ll only erase bits of the texture, and no the background! (so take care of the edges of the picture: you can use various erase tools to make the effect look nice, I personally always take one of the round ones – the square tools will always leave some edges)
Here’s the result:

Now merge the two layers, by clicking right on the first layer. Select: ‘merge with previous layer’. You can now edit your picture:

And that's all!




