Required Action : User should be add new rate from inventory.
Go to 'Rates and Availability'.
Select 'Rate Plan'.
Select the property.
User will navigating to Rate Details page.
Select room type.
Select Rate Plans tab.
Select the rate to be edit and click 'See Details'.
User is possible to edit all the section.
Price Adjustment
Number of Guest
By Night Stay
Save your each section changes.