Ghana U20 assistant trainer Yaw Preko says he learning the art of being a successful coach under his head coach Sellas Tetteh.The ex-Ghana international worked with the former Rwanda boss at the just ended African Youth Championship where they won silver.Preko has been cutting teeth in coaching at Accra-based lower division Westlands.But he says Tetteh's influence on him has been tremendous on his new career choice."The learning process, I am enjoying it. The way he is naturing me, including me in the selection and giving me the opportunity to express what I can do ," the former Anderlecht star disclosed on the Joy Sports Link on Saturday."It is marvelous working along with him. I know him way back over 20 years and this is the first time of working with him as a coach and I have learnt so much."Preko was also assistant coach to Orlando Wellington in 2011 Ghana U20 team which failed to progress from the Group stage of the African Youth Championship.