You said the "beeps changed" when you ran the throttle all the way up.

This is good. It indicates that the throttle channel is working as is the ESC.

It sounds like everything is working as it should be.

However you have not initialized the ESC, so it is not ARMing properly.

Do this...

0 - Bind your transmitter with your plane all over again.
1 - Turn on the transmitter
2 - Put the throttle TRIM all the way down.
3 - Put the throttle all the way down.
4 - Plug in the plane to it's battery ( turn on the plane ).
5 - Move the throttle all the way up, wait LESS than one second.
6 - Move the throttle all the way down.