what I mean is that your current ram is built in and cannot be removed.
But there is an extra RAM slot where you can add more rams.
You already have a 4 gb.
If you add a 2gb it will become 6gb
If you add 4 gb, it will become 8gb
If you add 8gb, it will become 12 gb
If you add 16gb, it will become 20gb
To do that, you gona have to open it up from the bottom and look for the RAM slot
Look at this thread to see the gut