Follow the advice you are given.
You really need to give those batteries the full initial charge to get the best out of them. Uncharged batteries are not going to produce the full vapor. You will add more liquid to get vapour, flood the atomiser and the batteries. Ask me how I know
Does it gurgle when you draw on it? Was the burning sensation from the taste of the juice?
Put 1 of the batteries on charge for a minimum 10 hours, whilst it is charging stand the atomiser cart side down on a saucer with some tissue underneath to drain all that liquid out. And avoid temptation to use it.
What cig is it? If it is a 901 try and avoid dripping and if you are topping off a cart, just make it moist on top. 2-3 drops is really all you need to add when you top it off. Too much liquid will give you liquid in the mouth which will taste real nasty.
I usually smoke off a regular kit cart and then top off with a flavour of my choice. I know you will want to get stuck in but you really need to be patient with it for the 1st day or 2.