The discount rate lets you express future receipts in today's money. The later a positive receipt arrives, the lower its present value, as long as the rate is positive.
An example with numbers
At a 10% annual rate, receiving $1,100 in one year is worth $1,000 today. Receiving that same $1,100 in two years is worth about $909.09 today.
Try it with your numbers
In two scenarios of equal length, place the same net receipt in different years. See how its discounted value changes even though the nominal total is identical.
Example figures for learning purposes. They are not a recommendation and do not replace professional advice.