Since it's likely a generic brand.... it may be a write off if you can't source compatible replacement parts.
The likely parts that could have burnt out are the ESC and/or the receiver. Sometimes these are all-in-one components and not separate items.
Typically, if it's typical... when you apply power to an ESC, you will get some tones played back. If you did hear tones before and not now... this is a good candidate for replacement. If you still hear the tones.... look at the receiver instead ( for now ). Remember there are two types of ESC's, one's for brushed motors and one's for brushless. On either, the replacement needs to match or exceed the amp output and support the voltage of the original ESC.
If it's the receiver... you must find a compatible receiver. For instance, with a Spectrum radio, they use DSM or DSMX protocols and Futaba radios use S-FHSS/FHSS or FAAST protocols... each brand often has it's own protocol so you'll need to find a compatible receiver if you are going to replace it or you would need to replace both the receiver and transmitter both.