Non-Lydia users must define the bank account to be credited (by entering its IBAN) from the link in the money receipt notification.
Lydia users receive their money in their Lydia wallet by default. They can modify this behavior from the "Preferences" screen to request that the money be sent directly to their bank account. (Click here from a cell phone).
Only Sumeria accounts are available at present, but all Lydia-compatible banks will soon also be accepted.