In the hopes that "there are no stupid questions...", could you please tell me what $500K against $800K means?

[A] against [B] means:

A = The amount of money the writer is guaranteed, basically the purchase price to acquire the project.

B = The total amount the writer will receive once the movie hits "commencement of principal photography" (i.e., the first day of production).

So in the case of "Father Daughter Time," the writer gets $500K for the purchase. If the movie gets produced, he gets another $300K.

In the parlance of the business, this is what is known as a high-six figure deal due to the all-in total of $800K.