To create a Rule, click on “Cashflow” in your sidebar. From there click on “(X) rules created” in the top right corner of the screen. 

From the Rules page, click the “Create new rule +” button in the top right corner. Set the parameters that the Rule will follow, which uses the format “If a transaction is <X>, then change it to <Y>.” 

Once you’ve set the parameters of a Rule, you can preview which transactions will be changed by clicking on “Preview changes” in the bottom left corner of the pop-up. 

If you would like to apply the Rule to your existing transactions (and not just new ones) make sure the box titled “Apply to X existing transactions” is checked.