Looking for Two Sticks of DDR4 4gb RAM

are you also upgrading your CPU? that board will only work with Intel's 6th and 7th gen CPU's. the last Intel CPU's that accepted DDR3 ram was Intel's 4th and 5th gen CPU's which are not compatible with that board.

you can buy ram from any computer website and it would be best to go to the manufacturers website and look at the QVL list to find ram that was tested to work with that board