Plum analyses your transactions and then identifies your regular income, rent, bills and daily spend. Using this and other factors like your available balance, Plum will work with you to help you set money aside!
The Automatic is the default rule - automatically turned on when you create your account and link your bank.
It will run every week and the amount it sets aside depends on your spending habits, bank balance and 'mood'. The default mood is 'normal' but you can edit the amount it sets aside if you go to Brain > Rules > Automatic > Mood.