how do you use algebraic notation if both of the knights can both attack the same square? i.e.- knight on c3 and knight on a3 (somehow) can both attack b1, so how do i notate the capture or movement to that square. is it like Naxb1/Ncxb1 or what?
You are correct…
Naxb1 / Ncxb1
Nab1 / Ncb1
Note that if the file is not good enough you can use the rank. For example,
N1c3 / N5c3
if you had nights at b1 and b5.