You can login your account on GDEX & trade the GDEX.BTC of GDEX against the BRIDGE.BTC of #CryptoBridge by simply opening the corresponding market:
https://gdex.io/market/GDEX.BTC_BRIDGE.BTC
https://wallet.crypto-bridge.org/market/BRIDGE.BTC_GDEX.BTC
And then withdraw BTC from GDEX.