Use the Pen tool to create the rectangle like shown in the image below. Start by creating the bigger rectangle with the color #2A1209 then create the smaller one with black. Switch to the Burn tool then paint around the left side to make it darker.
Pay attention how the layers are placed (one over another).
Draw some dots in the smaller black box using the Brush tool. Set the brush size to 4px and hardness to 70%. Set the foreground color to #622E19 then paint the dots into the smaller black box. Use the Polygonal Lasso tool to draw a rectangle like shown in the image below then fill it with white.
Now we will make the rosette. Create a new layer then select the Elipse tool (U) and draw an oval about the size of the one shown in the image below. We will work on the perspective/angle of the oval later. Fill this oval with dark red then go to Layer > Layer Style > Stroke. Create an inner stroke with a darker red (#652100) like shown in the image below. Duplicate the layer then make it smaller using the Free Transform tool (Edit > Transform > Free Transform). Scale the circle smaller by holding the Alt + Shift key while dragging one of the corner points. Fill this layer with a beige color. Remove the stroke on this layer by right clicking on the layer then selecting clear layer style. Do this one more time for the black hole. Duplicate the layer (Ctrl+J or Layer > Duplicate) with the beige circle then use the Free Transform tool (Edit > Transform > Free Transform) to reduce the size of the circle. Fill this circle with black. Select all three of these oval layers then go to Edit > Transform > Free Transform to adjust the perspective. You can hold down the Ctrl button while dragging one of the corner points to adjust only one point at a time.
Step 8 – Create the guitar neck
Create a shape using the Pen tool (P) like shown in the image below. Fill this shape with #532315. Use the Burn tool (O) to burn around the top of the neck to make it darker. Create the strings using the Pen tool (P).