Prepare 2 bolts assembly by inserting lock washer (#D), then flat washer (#E) onto bolts (#C). Align seat (#2) to the chair back (#1). Secure two middle holes of the seat (#2) by using bolts (#C), but do not fully tighten. Prepare 4 bolts assembly by inserting lock washer (#D), then flat washer (#E) onto bolts (#A). Secure corner holes of the seat (#2) by using bolts (#A). Fully tighten all bolts (#A,C).