The interchange at the Jalan Maju Flyover is pretty confusing. You need to keep right to turn left to Jalan Maju. If you wish to go straight on Jalan Megat Harun, you keep left to reach the traffic lights. The signboard is useless. It says go straight for Kulim and Alma, and turn right for Bukit Mertajam. While that is true, Alma is in Bukit Mertajam! And where you are is Bukit Mertajam too. Also, taking the right turn (rather than going straight on) will also take you to Kulim. So you can pretty much ignore the sighboard.
The southern end of Jalan Megat Harun terminates at the junction with Jalan Bukit Minyak, with the wall of the Jalan Alma flyover ramp right in front of you. Due to the flyover, you have to turn left (head east) in order to reach Bukit Minyak (which is on your right, or west), and turn right (head west) in order to reach Alma (which is on your left, or east). The signboard points correctly to the direction to go (though at first it may appear like you are going the wrong way, just follow it!)
At the Jalan Maju Flyover, go right to turn left, and go left to go straight on.
As you have to circumnavigate the flyover, turn left to go to Bukit Minyak (which is on your right), and turn right to go to Alma (which is on your left)!