What?
Legit means you should trust your source. You can search around the net and see what people say about your exact stuff. Other than that some of the signs of legit gear are...
Rounded corners on the labels.
All the amps are equally filed.
It's not from a ugl that's been busted.
It has a exp date and lot number.
It has a label.
It comes in the origional package (but not all the time)
The topper is on if it's a vile.
If the manufacture has a safety hologram it will be on what you buy.
Some of the manufactures you can check the numbers on their website.
As for the how can I attain to use it part I have no clue on what you mean. You should really know what you're using first. | 
