This function is only available in the Enterprise Solution.
To add training examples to the classifier manually, click on the classifier and then select the -button.
If you already have data inside your classifier, you can also open it and click on the top row:
Now the category can be entered on the left and the matching text can be entered on the right. The green checkmark means the example is confirmed and added, while the grey checkmark means it will be removed.
Expert tip: If you want to add many examples, you can switch between the different boxes by using TAB. Additionally, you can save the example by pressing SHIFT + ENTER.