How do I ping the map?

Some frineds of mine and I started to play DOTA 2 this weekend. Since we are some friends (not full team), we have some randoms with us.

But when we want to tell them to go some place, or to be carefull. None of us has any idea on how to ping the map.

How do you ping the map in DOTA 2?

Hold Alt and click on the map to ping. Hold Ctrl and you can use your mouse to draw.

Also, you can use the chat wheel for commonly used phrases quickly, hold Y and move the mouse in the direction of the phrase you want.
The phrases on the wheel can be chosen from a huge list in the options menu.