just to make things clear for you. I assume you have your throttle on the left stick of transmitter, and your rudder on the right stick?
Now, the complication is that the receiver is marked up as though its for a model aircraft, and they use different channels. The rudder on a rc plane, is the left stick, moving left/right. The throttle is the same up/down, rc plane ailerons is right stick left/right and the rc plane elevator is right stick up/down
So, for a club 500 which uses 2 channels, throttle is same, but... your rudder plugs into the ail (aileron) channel on the receiver
(all assuming you use the most popular UK set up of mode 2 throttle on left)
Make sure you have the connectors into the rx the correct way around, I don't have a planet 5 setup that is easy to see so cant remember which way around the lead goes
You will now have throttle on left stick, up, and rudder on right stick, lweft right. I seem to remember standard the planet t5 is not a self centring throttle stick, this is because rc planes don't have reverse! so you cannot go backwards with your club 500, although, your esc has the capability to do this. Its an easy fix, open up the tx, and remove the spring setup on the elevator (right stick) which you don't use, and fit to the throttle stick, viola, you now have a self centring stick, so you can now have reverse
You will need to reset your esc with the throttle stick in the centre, full forward, then full reverse, back to neutral. My experience of those esc's in my club 500's are they are good, but always check you still have full throttle. Other members in my club have mentioned that periodically the esc drops full throttle, no idea why, as we race, I check it every race day