Direct Activities are ones created without an associated Plan. To learn how to edit activities applied from plans Click Here.
In order to edit a direct activity select the Crops tab and then the crop the activity was applied against:-
Select the Crop History tab and then click on the activity you wish to edit:-
This will load up the activity screen where you will be able to change the details you need.
Once any changes are made clicking the Save button will save the data and take you back to the crop page:-