How do you open level editor

I’m new to using unreal engine 4 and i really need to know how to open up level editor

thanks everyone for your help i really am thankful! and can u link some videos on my problem?

sorry add my comments twice

These are tutorials directly to unreal engine ufficial youtube account. I often use them

Getting started with editor:http://www.youtube.com/playlist?list=PLZlv_N0_O1gasd4IcOe9Cx9wHoBB7rxFl

Getting started with level editing:http://www.youtube.com/playlist?list=PLZlv_N0_O1gak1_FoAJVrEGiLIploeF3F

Introduction to materials:http://www.youtube.com/playlist?list=PLZlv_N0_O1gbQjgY0nDwZNYe_N8IcYWS-

Introduction to blueprint:http://www.youtube.com/playlist?list=PLZlv_N0_O1gY35ezlSQn1sWOGfh4C7ewO

From these you can start looking for more vids and tutorial.

This last link is a full documentation of major topic of Unreal Engine 4

The large window/viewport in the centre is your level editor. Go to ‘file’ and you can make a new level or open an existing one. Objects in the level are in the ‘world outliner’ on the right by default and on the left you can find objects you can place in the level by dragging and dropping. Resources are at the bottom like materials, meshes.

A few months ago I was a newbe in Unreal Engine 4.
I really suggest you to look for a playlist of tutorials in youtube and spend some times watching lessons.
If you want i can share you some link