A primary source is a journal or book written by someone who saw history happen. In the French and Indian War, the best primary source available in English is (drum roll, please):
Adventure in the Wilderness: the American Journals of Louis-Antoine de Bougainville, translated by Edward P. Hamilton
Colonel Bougainville was aide-de-camp to General Montcalm, and his journal is a real gem, replete with information, even down to weather conditions on a particular day.
I highly recommend it!