The English government decided to send one of their most able generals, Braddock, to the colonies in North America because the French were preparing to attack the English colonies. There was only one problem: transportation.
The British army needed to be able to carry large amounts of food, weapons, and other supplies on their march; not only to use them against the French but also to give to the Indians for their friendship (unbeknownst to the British, most of the Indians had already gone to the French side).
This is why Braddock asked Ben, who was influential in Philadelphia, to help him get wagons, horses, and other pack animals to help them in their journey.
Franklin told the general that to be able to use the peoples' wagons, he would have to pay for them, and he agreed to help sign them up. He printed an article in his newspaper on how much people would be paid for the use of their wagons.
Soon, all the necessary equipment had arrived at the rendezvous point and the general was ready to march.