The phrase "are to begin a" is correct and usable in written English.
It can be used to indicate a scheduled or planned action that is about to take place.
Example: "The new classes are to begin a week from Monday, and students are encouraged to register early."
Alternatives: "are set to start a" or "are scheduled to commence a".
The Yankees are to begin a 10-game road trip tomorrow at Tampa Bay, continuing on to Chicago and Baltimore.
If we are to begin a cull not very nice people, there will be a lot of empty statue plinths and a lot of returned, or spurned, bequests.
Bruce Springsteen and the E Street Band are to begin a world tour on Aug. 7 at the Continental Airlines Arena in East Rutherford, N.J., in support of their new album, "The Rising".
Fresh from the battlefields of Afghanistan, more than 2,000 American marines are to begin a three-week exercise off the coast of Kenya on Sunday, military officials said today.
With oil prices at their highest level in a decade and the United States and other industrial countries calling for relief, heads of state and oil ministers from the 11 members of the Organization of Petroleum Exporting Countries are to begin a two-day summit meeting here on Wednesday.
[C20.] OPEC Prepares for Summit Meeting With oil prices at their highest level in a decade and the United States and other industrial countries calling for relief, heads of state and oil ministers from the Organization of Petroleum Exporting Countries are to begin a two-day summit meeting here today.
The key is to begin a beginning and experiment with deploying beginnings.
On Saturday, he was to begin a United States speaking tour.
Next month, he is to begin a two-year assignment in Shanghai as a consular officer.
Next month, she is to begin a fellowship in glaucoma at Wills Eye Institute in Philadelphia.
In July, he is to begin a residency in dermatology at the University of Pittsburgh Medical Center.
