2/ How to find posts that may already have the answer to the question I have?
One of the key benefits of the forum is that it enables commonly asked questions to be answered once, for the benefit of all. Before posting your question, it is always worth checking to see if it has already been asked - and answered! You can do this via the Search function.
Using the Search function, you can perform a quick keyword search, or click on the "Advanced" button to search by more specific criteria. Various options are available, both for how the search term is specified and for controlling how many forums you want to search. This is where the specificity of topic subjects is important; making it much easier to locate precisely what it is you're after from a list of search results.
The search button is located at the top of the page, to the right.