Why do we reference?The Study Skills website gives fantastic advice on referencing. Within the "How to reference..." pages are examples for referencing journal articles, books, conference papers, lecture or class materials and more. The examples also provide an indication of the quality of the source, whether it is a superior source, or a less preferred source to use.
The FedUni Library YouTube channel hosts excellent videos on how to reference using APA and Chicago Note styles. View the APA referencing ones here:
To check a reference as you go, try FedCite (APA) to find in-text and reference list examples. 
The Federation University General Guide to Referencing (pdf 3.1 mb) provides information on how to reference in APA, MLA, Australian Harvard and Chicago Note Styles.

Check that the highlighted matched text in your assignment is referenced correctly. You need to make sure you have included the in-text citation in the body of your work and you have a corresponding reference at the end of your document.
The text will remain highlighted and continue to contribute to your similarity index score. This is okay! If you have acknowledged other people's work and have referenced correctly there is no more action to take.