Halachik Conclusion:
Learn רמב”ם ה’ שבת פרק ג הלכה ד
https://hebrewbooks.org/pdfpager.aspx?req=14278&st=&pgnum=16
Does the Rambam rule like the Rabanan or like Chanania?
How do we conclude lhalacha?
Learn שולחן ערוך ס’ רנ”ג סע’ א which brings two opinions how to rule. See how the רמ”א concludes.
According to which opinion does the מחבר conclude?
Bring a proof
Learn Mishna Berura
https://hebrewbooks.org/pdfpager.aspx?req=60388&st=&pgnum=45
https://hebrewbooks.org/pdfpager.aspx?req=60388&st=&pgnum=46
https://hebrewbooks.org/pdfpager.aspx?req=60388&st=&pgnum=47
https://hebrewbooks.org/pdfpager.aspx?req=60388&st=&pgnum=48
https://hebrewbooks.org/pdfpager.aspx?req=60388&st=&pgnum=49