It's easy! With the payment method "bank transfer" your customer is not getting forwarded to its online banking page but is displayed your bank details automatically in the order confirmation mail. With this information he can transfer the money on his own before the order gets delivered. This is how it works:
"Payment methods" > "bank transfer"
Choose the countries in which this payment method should be allowed
Enter the bank betails to which the money should be transfered
Hit "create payment method" and you're done :-)
+Customers with no online banking can still transfer the money
Other payment methods under http://helpcenter.branchbob.com/branchbob-helpcenter-english/activating-payment-methods