Hi you are right this helps practitioners to see what their role allows and does not allow them to do in regards to working responsibilities.
1. Meeting the needs of children requires you to know what the needs are. Your role means you are a keyworker to a set number of children? This role means you work closely with a key child's parents (sharing information about needs)? You make frequent observations (how often?) that monitor the child's development and evaluate that infomration to identify needs?
2. Complying with legislation in your role as a level 3 practitioner would involve following the setting's policies and procedures and being aware of issues of confidentiality and data protection. You would be expected to report specific information through official lines?
3. Delivering better outcomes for children involves how you work with other professionals so that any advice & suggestions they have that would support a child can be used, for example in planning activities, organising daily routines.
You should be able to find information about all this in your job contract and saff handbook.
pages 142+ of this EYE book is also supportive reading
Hope this helps xx