To use Banker - You can keep it open as you use Rea1m Apps or check it periodically. The App has a main page and a Transaction page; You can navigate to these using the main menu located on the left side of the App.
This App doesn't really have any "know-how" when running it, because all it does is keep track of your Rea1m Currency and shows you Transactions to your "Account".
It's recommended you have this App if you plan on using Rea1m Products/Apps - Banker is the only way to keep track of your Rea1m Currency! Your Balance isn't displayed anywhere else.