The order of the pipeline stages matters, because the output from one stage becomes the input to the next stage. For example, the Solr Query stage must always come last in the sequence, so that data is indexed only after it has been processed by all other stages. Putting this stage first in the sequence means that subsequent stages have no effect on the indexed data.
Drag any stage in the pipeline to move it up or down in the sequence of stages. The preview panel automatically updates the search results to reflect the output of the new sequence.