How to Create a Dataprep recipe?

I am learning how to work with Cloud Dataprep by Trifacta on qwiklabs Streaming IoT Data to Dataprep. The instruction to follow is quite clear and I have not encountered any problems yet, but when I try to Create a Dataprep recipe (Split column On delimiter) with temp-sensor as the delimiter, I get this error:

Error Invalid parameter. Please ensure that the syntax is correct

This renders the Add option unavailable, and I can't proceed. What am I doing wrong and how can I proceed? The picture below:

Again, I realised that this is nothing complex. The delimiter should be in quotes( 'delimiter' or "delimiter" also would work).

In my case it is "temp-sensor-".

I guess learning anything at first seems complex until you actually do it.