I need some gerneral knowledge. Which one is the high speed needle, which is low speed needle? It runs for about half a tank then dies, won't start, then it acts like it powers out. Any help would be great.

Hsn is the one on top of the carb, lsn needle is generally in the middle of the throttle arm attached to the carb.

What is it?
Are you running it hard when it quits?
Is it getting too hot?
What engine is in it?...What percent nitro?
Lots of different factors to consider when diagnosing "runs for about half tank and dies". I would assume first that you are running the hsn too lean, and it's overheating, and then the carb is vaporlocking.
It is common for the carb to have to be adjusted every day that you run it. Maybe even several times in a day if the weather changes, or if you change something else...Such as cleaning the air filter, or opening a new jug of fuel.
A temp gun can be a handy tool for learning tuning. As a general rule, most nitro engines run best between 230 and 280 degrees F. If they run cooler than that, the sleeve doesn't expand fully, and accelerated wear will occur...leading to sooner rebuild. If they run hotter than that, there isn't sufficient oil in the fuel to properly lube it...again leading to accelerated wear, and the whole rebuild thing...

Its a trinity nitro spyder. with a .256 ci, 4.27 cc motor, 20% nitro. I am completley new to the sport. I have only owned this truck for two days. I have read the instructions 50 times but they don't go into detail about the stuff they tell you to do. So to me the directions might as well be writen in greek!!! I know my questions are probably stupid but i really don't have a clue! Thanks for your help.

Don't get discouraged. There is a pretty steep learning curve in the beginning, but it gets way easier fast.
Search around on the forum for some of the answers, as there are some pretty learned folks that hang around here, and have put up some nice tutorials.