The work to be done consists, in general terms, of co-ordinating all the arrangements for the operations undertaken and carried out by the several armies; the issuing of general orders and instructions for operations, the details of which were worked out by the armies concerned; the issuing of orders for the movement of divisions, of artillery units, cavalry, and Tanks--in fact, all the different services which go to make up the Army.

These orders must be so arranged as to fit in with the roads and railway facilities, or the mechanical transport available, and must be so couched as not to interfere or clash with arrangements made by the armies in the Army areas.

This necessitates very intimate _liaison_ with the armies and with the departments concerned.

Maps have to be kept up to date, showing the dispositions of troops at all times, both on the battle-front and in back areas.
"In addition, there are the arrangements with our Allies, the fixing of areas between ourselves and our Allies, and between our own armies and the lines of communication.

During operations messages have to be sent out giving information of the situation to the troops, to the public, and to the War Office at home.
Schemes are worked out beforehand to deal with any possible eventuality, so that in the event of a hostile attack the movement of troops may be carried out with the least possible delay.
Similar schemes are worked out for operations to be undertaken by ourselves, and methods of attack are thrashed out in consultation with the Army Commanders and Staff.