Repeat steps four and five to place the other side panel. Apply the glue along one edge of the base and side sections. Position the front panel on to this, ensuring all edges are flush. Wipe away any excess with a damp cloth. 7 Hammer in panel pins along the edges of the front panel to hold it in place while the glue is setting.
Repeat steps six and seven to apply the back panel to the base and side.
8 Glue two 25mm x 25mm wood sections, which will act as feet, to each end of the base. To counter any slope of the window-sill, plane the feet to achieve the right angle. With the construction of the box completed, add some shop-bought decorative wood mouldings to the front panel. Wood glue can be used to apply them to the front of the box. This is a good stage at which to fill any gaps in the panels with an all purpose filler.