This method is to keep the placket completely hidden on the right side. Fold along the placket line and pin at the placket closing:
Place placket cover over the first half of the opening and sew:
Complete the same for the other side:
Press open:
Lay placket line in a straight line and pin material bulk flat. Press and prepare for topstitching:
Final output:
Alternatively, this is another way to deal with the bulk material when applying the final topstitch so that the appearance of the fold on the right side is different: