It's nothing difficult. Declaration means that you go to the bank and the bank will ask you to fill out a declaration form.

Friendly reminder, you don't have to declare too much money at one time, otherwise it may not be approved.

In addition, when you declare, fill in the reasons for your declaration. It is recommended to write salary income or transaction income (you may be required to bring it)

I suggest you ask the bank for details. They are more professional than us.