Paste your draft into the editor, choose a tone, and run it. There is no setup and no configuration beyond the tone.
Start with a real document rather than a sample sentence. Everything in this category handles a paragraph well; the differences show past about 1,200 words, where repeated connectives and uniform sentence length begin to surface. The free plan takes 1,500 words in one scan for exactly this reason — a standard undergraduate essay goes through whole.
Read the output against your original rather than replacing it wholesale. The rewriter is good at breaking up flat rhythm and removing connective throat-clearing. It is not good at knowing which of your specific word choices carried meaning, so some of what it smooths was doing work.
A practical habit: keep the original in a separate document. That gives you something to compare against, and if the piece is academic it also gives you the version history that matters far more than any detector score if your work is ever questioned.
If the output reads worse rather than better, the usual cause is that the source was already in your voice. The rewriter helps most with text a model drafted and least with text you wrote carefully yourself.
Run the detector on the result if you want to see where machine-typical patterns remain. Treat that as information about the writing rather than a prediction about what any institution's detector will conclude.
One habit worth forming early: run the detector before the rewriter, not only after. Seeing which sentences were flat in your original tells you whether the draft needs rewriting at all, and sometimes the answer is that two paragraphs need attention rather than the whole piece.