LG enV VX-9900

Hi, I just ordered my Env Orange and would like to know how long I will need to charge it before I use it for the first time. Will it have a partial charge already? Or is it best to charge it first? Also I downloaded a manual earlier last month that read that I should not answer or make a call while the phone is charging. Is this a valid warning and is it only for the home carger? I noticed that the car charger is stated to charge the phone while you use it.
Thanks