Officials on Monday morning voted in favor of a contract that’s designed to kickstart the long-awaited transformation of a public building behind Town Hall from a defunct teen center to a useful, rented commercial space. The Board of Selectmen voted 3-0 to approve a $44,000 contract with Woodbury-based Gary Numberger, Architect LLC for design and engineering services in connection with the former Outback Teen Center. The New Canaan Department of Human Services is to move into the ground floor of the building from its current home in Vine Cottage, while a dance studio rents space on the main floor. According to Department of Public Works Building Superintendent Bill Oestmann, the municipal agency will get a dedicated new entrance from the Town Hall side of the Outback. “It will be more inviting,” he said of the planned new entrance, and the Human Services Department will also move into renovated space with offices and a conference room.