In addition, the involvement of stakeholders is regarded as important; training evaluators and ECEC staff and management on implementation of monitoring systems is key to success; and monitoring practices of child development should be designed to be developmentally appropriate.
OK, thanks. It was the lower-case 'training' that was unclear.
Verb: Training on Who: ‘evaluators and ECEC staff and management’ What: implementation of monitoring systems Object: is key (meaning essential) to success.