I use to make mini site designs for friends.
Here are some examples.
Now these sites were design only for graphics for sites, Not the layout, but as you will see i used a basic layout with guides once i new what size i wanted the graphics to be,ie... the hight and width of the header and footer, then everything else work around that, these are not complete by the way but will give you an idea on where to start laying out your plan in Photoshop. The real Finnish ones had groups with the background, main layout, footer, header, bullets, text fields, testimonial box's, ones for sign up forms where the forms could be imported in to them, and each one of them had guides so the images could sliced and then exported from Photoshop, so on and so on . The example you have looks very basic, you could break it down in to boxes and just add pictures in , nav bar's exct. , I only posted this on the assumption you have been ask to just produce a graphical image of a web site design layout.