Complex sentence: Members of the Druk Gyalpo's Secretariat began to use flags of a new design during the trip based upon a photograph of the first national flag of 1949 with the colour of the dragon changed from green to white.
Split into simpler sentences: Members of the Druk Gyalpo's Secretariat began to use flags of a new design during the trip. The flag was based upon a photograph of the first national flag of 1949 with the colour of the dragon changed from green to white.