Need help understanding "Index" and "Match"

=MATCH(look for what, look for it where, 0 for exact match)

=INDEX(using what table, pull reference from row #, pull reference from column #)

Assuming A1:A10 are 10-1 (in reverse), then MATCH(3,A1:A10,0) = 8 because the 3 would be in A8, the 8th row down.

=INDEX(A1:C10,3,3) would pull the value of C10, the 3rd row and 3rd column in.

=IFERROR(

INDEX($C$5:$X$241, = the table
MATCH(ROW(BX1), $J$5:$J$241,0), match the row # to the value in J5:J241 = Let's pretend this = 10
MATCH($K$5, $C$5:$X$5,0)), match whatever is in K5 in C5:X5 = Let's pretend this = 3

"")

With the above values, =INDEX($C$5:$X$241,MATCH(ROW(BX1), $J$5:$J$241,0),MATCH($K$5, $C$5:$X$5,0)) = the value of E14. It's 10 rows down from C5 and 3 columns in.

Here's an example if you need a visual reference.

index - match for beginners.xlsx