Hi, this can be so daunting, as recommended take some time to research, it will come together for you xx
These may help to start ..
Attatchment theory - John Bowlby and Mary Ainsworth - key person systems
Jean Piaget on openlearn and basic introduction from
Educationscotland
One educational approach that influences practice & frameworks is Reggio Emilia - also from
Education Scotland
A nice beginning that familiarises a reader with some of the many threorists is the
How children learn series by Linda Pound & Cathy Hughes, maybe ask if your library has a copy available?
Best wishes with it xx