Piecewise functions are usually the easiest graphs to do. Don't worry!
This graph is in three pieces. Every piece, the function immediately to the right of the bracket, is followed by its condition right after; the "if..." part. If you take any x-value from -∞ to ∞, it will go into one of the three pieces. Which piece it goes into is determined by the condition.
Just looking at the slopes, you can tell that the left side of the graph (for x less than or equal to -1) will be a negative line coming down from +∞ on the y-axis. For the middle piece, there is a horizontal line between x = -1 and x = 2. For the right, there is a positive line going to +∞ on the y-axis.