The smallest cross pieces should be on the end of the antenna pointing toward the transmitter. The main beam, or part that connects to the pipe would be pointed toward the transmitter with the shortest cross pieces first. Should look like a triangle pointing at the transmitter.
Yes, the extendable arms are perpendicular to the line of sight to the transmitter (shortest arms first).
The antennaweb.org website can provide a compass direction for you if you enter your zipcode.