If you want to have more ram, then it's best you populate the board with the maximum ram it can handle after distributing it evenly across all ram slots in order to avail dual channel memory configuration. Take ram upgrades as though you were buying shoes, you can only buy them in pairs not in singles. Speaking of which you forgot to mention your full system's specs as well as your OS.
List them as:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
^ please be specific about the make and model of each. If you can't pass on the information to the rams, then best pass on a link to them.