Yes, that’s how it works…
You can purchase straight from trust wallet - just make sure you input there correct recieving address -
eg 0x******************* is ethereum and bsc is built on ethereum virtual machine so any coin on the ethereum or Binance smart chain networks will have them same address…
If you send from somewhere else, go to CMC, FIND THE CONTRACT, then you know the network-: add the coin following instructions from other reply