Hi a,
My name is Riccardo and I'd be happy to assist.
Generally when you install more RAM the Operating System just takes that additional RAM and adds it to its physical memory allowance. If you are not seeing the additional RAM there are a few troubleshooting steps we can perform.
Step 1 - Is it showing up in the BIOS?
Can you go into the BIOS settings of your computer and check if it shows 16GB vs the 8GB you had before?
Step 2 - Is there a software limit that is causing the extra RAM not to be seen?
Click Start > type in msconfig
Press Enter
Click on the Boot Tab
Go to your Windows 10 Install (loaded on the C:\ Drive)
Click Advanced Options
Is there a maximum memory lock?
If so, unclick Maximum Memory...
Step 3 - Is Windows 10 actually reading 16GB of physical memory?
Go to Start > type in System
Click System Information
Under Installed Physical Memory is it showing 16GB?
Let me know if the above helps you, if not I will be here to assist with further troubleshooting steps.