The piece on this pages just cut them normaly! Now the just glue the 3 other piece on cardboard and cut them.
Only measure 1 cm from the right point of piece D then glue piece C on it (see the photo) - Glue them together, put the glue sticke on the back of the big piece, glue it on cardboard then cut it following the lines. When you finish cutting pull off the white paper. Now cut of the whole piece by flowing the lines.
I put the glue stick on the back of the big piece and I glue it on cardboard. I place piece A on piece B make sure to connect edges well. Piece B : I put the glue stick on the excess of the straight.
Piece A : I cut off the excess from the straight line that will be the middle of the big piece (see the photo). We have 4 piece now, Take the A and B, this two we should glue them to get one piece. Cut the piece on page 1 and 2, I let about 0.5 cm to 1 cm away from the lines.