You are....well they are. Anyone occupying a property in Bands A to D ( and band E if there's a disabled reduction in place) at 1st April is entitled to a £150 payment.
In the case of DD payers it's paid directly to the bank once the first instalment has been confirmed as paid.
Everyone else has to make an application stating whether they want £150 paid directly or taken from their Council Tax bill.
There is no standard application process i.e., every Council could have a different method for the application to be made.
There's also a discretionary scheme, the Government leaving it to each Council to decide what criteria for the scheme.