How can I fix Renault Megane camshaft dephaser?

05 megane 1600 vvt camshaft dephaser. I'm led to believe from previous enquiry that after fitting new dephaser, the ECU would require reprogramming. Renault main agents say this is not necessary unless camshaft sensors replaced as the dephaser is mechanical not electrical! Apparently the dephaser requires "locking or setting". My question is how? Is this procedure done with sprocket off the camshaft or on. I'm also informed it is set by twisting so therefore is it twisted clockwise or anti-clockwise and by how much a quarter turn, half turn or more?