Draw a slanting line
Copy & paste it
Flip the copy horizontally (Draw/Rotate or Flip/Flip Horizontal) and move it
to touch the first one to make a V shape (or an upside down V - it doesn't
matter
Group the two lines.
Copy and paste to get another V. Move that to touch the first.
Group them all and copy and paste again.
Repeat until your zig - zag is as long as you want
Lastly, buy me a donut for doing your homework