2 strips 9cm x 27cm outer
2 strips 8cm x 24cm Middle
the third A4 card put the card landscape and cut 2 strips off the end 7cm these two strips will measure 21cm x 7cm inner the left over piece trim to 15.5cm x 15.5 cm this is your lid
and finally the 2 inner pieces and score them equally 7cm as per diagram
The flaps should all fold up ready for the lid.
fold each score line in and the corner diagonal fold should fold flat against the inside edge use a wet glue and paper clips to hold position until dry.
Now your box is ready to be embellished