Ah, no problem at all.

The layer mask means that you're only going to see the areas that are white on the mask. So the layer mask on the gradient pattern means that you're only showing the land colours over the land areas - so you won't have a green sea.

The emboss layers were taken from the image you have in your tutorial. I just copied in your green land layer. I then desaturated it (Colours->Desaturate).

I place this layer over the gradient layer and set the blend mode to soft light. This lightens the gradient of colours where the 'embossed layer' is lighter and darkens it where it is dark. I duplicated the layer as this increases the lightening and darkening effect. So the embossed layers give you the light and shade, the gradient layer gives you the colour.