This is just a Hello World lab to get you started using LaTeX.
You should start with the file LaTeXLab0.tex. Or, assuming you plan to use Overleaf, as described below, save the file LaTeXLab0.zip I suggest that you should use Save As to save the file to a cs191 directory that you create on your Y: drive. Or you can save the file to a directory on your own device, if that is what you are using.
Start Overleaf by clicking on the Overleaf link. You will need to create an account the first time, but it is free. Once you have an account you can choose New Project (a green button on the upper left), choose Upload Project, drag the LaTeXLab0.zip file into the window, then open it. This will show you the LaTeX file on the left and the result of processing the LaTeX file on the right.
Your assignment is to modify the document so that it has your name, Truman username and today's date. Then you should change the displayed math to assume x has the value 2k+1 instead of 2k and update all of the algebra accordingly.
When you are happy with the formatted document on the right side of the page, you will upload both your LaTeX source file and your PDF file using the Homework Submission page. This page will assign a timestamp to your submission and that will determine whether your assignment is on time. Any time until 11:59pm on the due date is considered to be on time.