erc20 btm swap

[bytomistheone]

Can someone please explain the process to swap etc20 btm to mainnet btm.  Do we have to swap with one of the exchanges like gate.io that are accepting the swap, before we can send to bytom mainnet wallet.  Or can we send erc20 btm directly to bytom mainnet wallet and get swapped there?  I can not find an explanation anywhere on how or when to do this?
Thanks a lot.