Thold stands for throttle hold. one of the switches on the top is labelled th hold as well. If you have the throttle hold setting on you will need to flip the switch before you can throttle up. Its like a safety feature so the main rotor or prop doesnt start spinning while you are handling it.
start with an e-flite blade MSR with a 6ch radio, the dx6i radio from spektrum rocks.
yes .. the reason is easy. align helis dont come with a radio or receiver so you pick the one you want .. i have a dx6i with my trex 450 v2 sport.. flys great.. good luck you have a lot to learn