There are 2 ways to reference in-text: Paraphrasing or direct quotes.
Don't overuse direct quotes in your assignments but if you do want to use them remember you need to use quotation marks and include the author, date and page number (paragraph number if no page number is available).
For example: According to Howatson-Jones (2016, p.10) "Individuals are unique, and human factors may be uncertain, even messy."
"preparation is very important, it can make or break your chances" (National Union of Students, 2013, para.6).
Howatson-Jones, L. (2016). Reflective practice in nursing (3rd ed.). London: Sage.
National Union of Students. (2013). Surviving first year exams. Retrieved from https://www.nus.org.uk/en/advice/careers/features-surviving-first-year-exams-/