Experimenting with layers in Photoshop

In today's class I experimented with using layers in Photoshop.

What I did to create this image:

1. Created a new document and filled the background with a dull green colour.
2. Created a new layer which I called 'Grass'. In this layer I selected the brush tool and in the brush's option bar I chose the Dune Grass brush. I then held down the mouse button to create a grass effect using different greens. 
3. I then created another layer called 'text' and in this layer I wrote out the word Lost. I then moved the 'text' layer in the middle of the background layer and the grass layer. This way the text is in front of the background but behind the grass. 
4. Next I created another layer called 'circle' which I placed under the grass and text layers. I then used the Elliptical tool to create a circle. Due to where I placed the 'circle' layer the green circle in the picture is in front of the background but behind the grass and text.  

After this exercise I am interested to explore layers further. I am also more confident with using Photoshop.