Another piece of the process of opening Westwood’s new public library has begun to fall into place. Last week, contractors began the task of moving the 200-ton Colburn School from its location in back of the new library. The school will end up next to the new library, in the spot of the old library, which was recently demolished. In the months to come, the 1876 school building’s first floor will be transformed into a bank, with six housing units developed on the floors above it. The Colburn will be rotated 90 degrees to face the new library, then exterior and interior work will begin. Westwood is one of several communities south of Boston that have been able to either build a new library, or renovate or add on to an existing one in recent years.