Start the back the same way you did the seat by using the reference image, clicking on the X-Ray view style and drawing a box. Go ahead now and make it a component called “Seat Back”.
Now copy it a couple times and rotate it appropriately aligned with the other views just like you did with the seat. The top left view won’t line up with the seat at this point but that is fine, we will correct that later.
Before you draw the profile for the seat back, edit the seat back component and rotate it into place. This is backwards from the seat we did before but the angle of the back is much greater so this way will be more accurate. You may need to enlarge the box
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