Energy shield - please help

Hello guys,
I got a question about energy shield. I aiming for a skill tree and still not sure which passive skills to take and so on...So I started to calculated how much resistance, energy shield damage crit and so on Im gonna have at lv certain levels so I know what stats I can focus on gear.
The problem is I don't know how to calculate the energy shield. The passive skill nods says "x% increased energy shield". What does that mean? So if I have 500 energy shield and I take 1 of those passive skill nods then it's going to be 540? And if I take another "8% increased energy shield" it will be 8% of 540?
Sorry if this is a stupid question I just want to be sure.
Thanks in advance.

No the nodes are additive so you add them all up before you multiply it with your ES.

EDIT: like two 8% nodes would be a 16% increase of 500.