Hi,
Please have a look at this example: https://www.knime.com/nodeguide/other-analytics-types/text-processing/dictionary-based-tagging
In short, you need to provide the Dictionary Tagger with sentiment dictionaries. Note that you will have to use one tagger node per sentiment (e.g. one node for positive terms, one for negative terms).
You can then do the classification as shown here: https://www.knime.com/nodeguide/other-analytics-types/text-processing/sentiment-classification
Hope that helps!
Cheers,
Roland