Compound Savings Calculator I Dont Understand Compound Interest?

I dont understand compound interest? - compound savings calculator

http://banking.about.com/od/savings/ig/Compound-Interest/

This page says it all that interest payments compound interest from the filing date

http://banking.about.com/library/calculators/bl_CompoundInterestCalculator.htm

because this link calcuate APY is only once a year.

so which is correct? CUS Trying to register in a savings account, and HSBC said they received a monthly