To automatically create a set of folders when a new lead is created, navigate to Settings > Data Setup > Project Types.

Click the ✏️ icon next to the project type, and a side drawer will appear. You can edit the project type's name and the standard project duration (in months). Note: changing the standard project duration will change how the cashflow forecast is calculated.

Finally, to create the default folder structure, which will be automatically created when a lead is created, click the + Folder button and enter the name of the folder. Multiple folders can be created and saved, and sub-folders can be created within folders.