Autopilot can be activated by first right clicking a system and setting as destination, then toggling with the little button
At this stage of the Alpha Autopilot is only effective traversing along star-gated systems, however travel speed will be slower than manual guidance as it tends to wait some time before entering star gates.
Another consideration is due to the slower speed in transitioning between zones, you are much more vulnerable to PvP players who may take this opportunity to hunt you.