StellarSdk.Network.useTestNetwork();
// channelAccounts[] is an array of accountIDs, one for each channel
// channelKeys[] is an array of secret keys, one for each channel
// channelIndex is the channel you want to send this transaction over
// create payment from baseAccount to customerAddress
var transaction = new StellarSdk.TransactionBuilder(
channelAccounts[channelIndex],
StellarSdk.Operation.payment({
source: baseAccount.address(),
destination: customerAddress,
asset: StellarSdk.Asset.native(),
// Wait a maximum of three minutes for the transaction
transaction.sign(baseAccountKey); // base account must sign to approve the payment
transaction.sign(channelKeys[channelIndex]); // channel must sign to approve it being the source of the transaction