Here's some information about citing your sources using ACS Citation Style, with an additional page of ACS citation examples. There's also a list of citation managers, which you can use to collect citations from various sources, organize them, and embed formatted references back into your papers. The examples are partly based on the ACS Guide to Scholarly Communication (direct link to the References chapter). If needed, you can also refer back to the 3rd edition of the ACS Style Guide.
UC San Diego has trial access to the ACS Guide to Scholarly Communication through the end of 2020.
It's important to cite the sources in your writing (also posters, presentations, etc).
It's difficult to completely copy the citation formatting as seen on the published ACS journal articles:
For a student paper, the simplest approach would be to use the HTML version, with parenthetical numbering of citations within the text, followed by a numbered references list without indenting. But you should also consult with your instructor if needed.
Comparison of citation formatting between published HTML and PDF versions of the same article in Industrial & Engineering Chemistry Research. Click to enlarge.