Question about Compound Interest Calculator

[Kiril Ivanov]

Hello,

I've read the BRRRR book (a great book) and checked its Compound Interest Calculator available at:

http://greeneincome.com/tools/

In the first unit given as an example there we have the following table details:

Mortgage #1
Initial Investment	$125,000
Mortgage %	80%
Mortage Value	$100,000
Note Income %	12.00%
Monthly Note Income	$1,000
Monthly Expenses
Insurance	$40
Taxes	$55
Mgmt. and HOA fees	$100
Mortgage Interest Rate	4.5%
Mortgage Expense	$375
Total Monthly Expenses	$570
Monthly Rent	$ 1,000
Monthly Rental Profit	$430
Monthly Note Income	$1,000
Total Monthly Profit	$1,430

I am having hard time understanding what does the "Monthly Note Income" means and where does it comes from. I presume it means "bonds" but I am not sure if this is the case. In addition, how do we get to that income.

I can see that we have the Monthly Rent Income and then the Monthly Note Income, how do we get to receive the note income of 12% / year, cause that seems to be quite important in addition to the rent. Do we basically just add the money that we own (and take from the refinancing) to an investment tool that is secure enough and can make us 12% / year?