Learn the “גמרא דף מב: “יכול לאכול כזית (second line from top of the Amud) until the end of the Perek.
Distancing oneself from צואת קטן:
Questions:
At what stage does the צואת קטן have the status of צואה; when the infants that age start to eat foods from the five grains or when this child personally starts to eat them?
If a child started to eat food from the five grains but them stopped for a long period of time would his צואה lose the status of צואה?
Learn טור אורח חיים ס’ פ”א סעיף א with the בית יוסף and the ב”ח
https://hebrewbooks.org/pdfpager.aspx?req=14265&st=&pgnum=146
Learn the שולחן ערוך ס’ פ”א סעיף א and see the מגן אברהם
https://hebrewbooks.org/pdfpager.aspx?req=14326&st=&pgnum=129
and the conclusion of the משנה ברורה
https://hebrewbooks.org/pdfpager.aspx?req=60386&st=&pgnum=234