Learn the גמרא דף יז. “אמר רב גידל (second line from top of the Amud) until איתמר (eleven lines from the top of the Amud)
Questions:
Is the qualification “ובלבד שלא יהא בית סאתיים פנוי” only for the opinion of the חכמים or even according to ר’ יוסי ברבי יהודה ?
Learn ריטב”א דף טז: “שלשה נעשו שיירא
https://hebrewbooks.org/pdfpager.aspx?req=37287&st=&pgnum=26
Would four people receive an area of eight סאה?
Learn ריטב”א דף יז. “ופרכינן ואלא
(same link)
According to the conclusion of the Gemara that a group of three can enclose a large area as much as they need as long as there is not an extra 2 סאה of unneeded space.
What is the halacha of a group of three enclosed 6 סאה but only needs 4?
Learn בית יוסף ס’ ש”ס, א “”ומ”ש ובלבד שלא יקיפו and the ב”ח
https://hebrewbooks.org/pdfpager.aspx?req=14268&st=&pgnum=126&hilite=
See ט”ז ס”ק ב
https://hebrewbooks.org/pdfpager.aspx?req=14325&st=&pgnum=225
Halachik Conclusion:
Learn שולחן ארוך ס’ ש”ס סע’ א and משנה ברורה
https://hebrewbooks.org/pdfpager.aspx?req=60389&st=&pgnum=46
https://hebrewbooks.org/pdfpager.aspx?req=60389&st=&pgnum=47
Continue learning the Gemara until the Mishna