Season One - 13(?) installments. Some episodes follow A/B plot, some only have A.

S01E01 - Zach and Kevin move to Jersey, explain their past life, ends walking into school?
S01E02 - Zach and Kevin meet Amelia, assigned class project to learn of their classmates - Kevin meets Gabriella, assigned as her partner; Zach and Amy are also partners, due at the end of the semester.
S01E03 - Whatever plot involving Zach and Amy, learning about each other; Kevin joins an art class, finds his "archenemy" (humorous).
S01E04 - Gabriella spends the day babysitting her seven year old sister - she asks Kevin to help, he reluctantly agrees.
S01E05 - Claire Wilkins, an Australian exchange student, makes friends with Kevin, to the slight (secret?) dismay of Gabby.
S01E06 - The gang (Kev, Zach, Gab, Amy) heads to the town fair (or perhaps somewhere less cliche, wedding? undecided) - a bit awkward, but the character dynamic begins to show through.
S01E07 - ???
S01E08 - Zach and Amy go out for brunch - everything goes wrong, they have fun though.
S01E09 - Kevin heads to Gabriella's house once again, to learn more about her; meets her mom; learns of her deceased father.
S01E10 - ???
S01E11 - Last day of school, freshman year - unknown plot otherwise.
S01E12 - Gabriella gets a summer job - she hates it.
S01E13 -  Kevin gets to know Claire, her mom is a famous Australian ex-reporter.

Season Two - 15(?) installments. Some episodes follow A/B plot, some only have A.

S02E01 - Kevin gets a job
S02E02 -
S02E03 -
S02E04 -
S02E05 -
S02E06 -
S02E07 -
S02E08 -
S02E09 -
S02E10 -
S02E11 -
S02E12 -
S02E13 -
S02E14 -
S02E15 -

Season Three - 17(?) installments. Some episodes follow A/B plot, some only have A.

Season Four - 20(?) installments. Some episodes follow A/B plot, some only have A.