Here are some hints on how to use PF (for more, see INFO at the top of the page):
For general technical questions, post them in the appropriate technical forum (start the thread by filling out the form at the top of the forum) and include links to your reading that you've been doing and ask questions about that reading. In some of the technical forums the thread title will include a prefix that you can set to B/I/A for Beginner/Intermediate/Advanced for the level that you would like the replies to be. I is undergraduate university level, and A is graduate school level and above.
For schoolwork-related problems, post in the Homework Help forums and fill out the Template that you are provided there when starting a new schoolwork thread. That includes the Problem Statement, the Relevant Equations, and your Attempt at the Solution. Always show your work on the problem so that we can then provide tutorial help.
The Homework Statement is where you list the problem word-for-word as it is given to you. You can also upload a PDF or JPEG image of the problem if that helps, but it's usually required that you type the problem in as well. The Relevant Equations section is to help you think about and list the equations and formulas and concepts that may be helpful in working the problem. You then show your work in the section below (the main body of the thread start).
To post math equations, it's best to use the LaTeX engine that PF provides. There is a helpful "LaTeX Guide" link below the Edit window to get you started. Note that you put double-$ delimiters at the start and end of each stand-alone line of LaTeX, and double-# delimiters at the start and end of in-line LaTeX that does not need to be on its own line.
Example of in-line LaTeX: ##v(t) = L \frac{di(t)}{dt}##
Example of stand-alone LaTeX:
$$v(t) = L \frac{di(t)}{dt}$$
Also, if you right-click on a LaTeX equation in a post, you get a pop-up menu to let you view the LaTeX source or view it in other formats.
LaTeX isn't supported in thread titles, so you can use simple text math in titles if you want.
Note also that PF uses a feature called "lazy LaTeX rendering" that speeds up page loads. When you first post your LaTeX in a thread, you will not see it rendered that first time. Just refresh your browser page to force it to be rendered, and then it should render whenever you come back to that page/thread in the future.
If you have trouble using the Preview feature to check your LaTeX, you can use a website such as https://www.quicklatex.com/ to preview your LaTeX before you post it.