Forecast Items can be created against any Account within your Organisation's Chart of Accounts on Futrli, with the exception of special-cased Accounts such as Retained Earnings.
To create a new Forecast Item, you will first need to locate the Account against which the Forecast Item will be added to. There is a search bar in the top right which can be used, otherwise, the Account will be located as per the Chart of Accounts:
Pressing the green plus sign adjacent to the Account in question will load the window where you can create your Forecast Item:
This Help Guide runs through your Forecast Item options!