What does this excel formula mean?

Hello,


Wondering if someone can assist and tell me what the following excel formula is doing:

=IF($C$68<=O2,IF(N12>$D$98,$D$98,N12),0)

Context: Forecasting

$C$68 - Cell is showing 1/4/2018 (Remediated Start Date)
O2 - Cell is showing SEP-18 (Forecast Month)
N12 - Cell is showing 15000 (from the previous forecast month)
$D$98 - Cell is showing 15000 (Remediated volume of 15000

Appreciate anyone who can assist :)