Preliminary orders were received on 9 May , ordering the separated detachments to move to a pre-arranged concentration area .
Shortly afterwards a second order arrived , informing the assault force that Fall Gelb was to begin at 05 : 25 on 10 May .
Preliminary orders were received on 9 May , ordering the separated detachments to move to a pre-arranged concentration area , and shortly afterwards a second order arrived , informing the assault force that Fall Gelb was to begin at 05 : 25 on 10 May .