Add Training data
One way of adding data is import it in the Rasa NLU format (JSON). You can do that from Settings > Import in your model
You can also copy paste or type a bunch of sentences in Training Data > Insert Many and select an intent to tag them all at once
You can also use Activity > Populate to add data.
If your model works decently, this can be a fast way to enhance your model: add a few examples, Rasa NLU will interpret them and display the annotated results in the New Utterances tab. Making corrections will be very fast, and you might find out that some examples are not that useful. Remember, you should only add more data when it makes your model getting more accurate.
Finally you can add examples one by one from the NLU playground. Just click on the interpreted example to open the editor
Then make your annotations and save.