Create our Document at 800 pixels by 600 pixels. Make sure the Units are set to pixels. Turn on Smart Guides by hitting Command + U. In our General Preferences set the Keyboard Increment to 1px.
Create a layer and give it a name of "Box Template." Then turn on Outline Mode (Command + Y), so we don't get distracted by fills and strokes.
We start with simple shapes. Draw a rectangle at 150 px by 150 px. Then select it and Duplicate it (hold Alt + Shift while dragging upwards) and set its size to 155 px by 65 px. Next, select the Pen Tool and draw the ribbon outlines following the box contours. Leave some space between the line and boxes.
Select the ribbon outline and choose the Reflect Tool (O). Then drag the rotation center point to the bottom anchor point, as shown below. Move the cursor to lower top anchor point, and while holding Alt + Shift, move the cursor to the right or left. The ribbon path will be mirrored, duplicated, and perfectly horizontally aligned at the same time. Then Save the file.