I feel really stupid asking this but how do I post a question ? What I mean is if I'm searching for a fic and only know some or very little about it is there a certain place I need to be in order to ask if any one knows it?

If you're looking for fanfiction, you should go to fanfiction alley.  There are a variety of fandom specific threads there.  You can post your search question on the appropriate thread for that fandom.  If there is no thread for the fandom you're looking for, then you can start a thread for that fandom. 

Just in case you're looking for Twilight fanfiction, here's an overview of the Twilight threads:

You can get recommendations and just chat with other Twifans here: You are not allowed to view links. Register or Login

If you are looking for a particular story, even if you only know the plot and not the name or author, you can ask about it here: You are not allowed to view links. Register or Login

We also have a thread for non-canon Twifans and a thread for Wolf Pack groupies.

Our Index of uploaded Twilight stories is here: You are not allowed to view links. Register or Login

You can find the links on the home page and clicking on fanfict alley.  Be sure to read the opening posts (first post that appears on each page of thread) for guidelines and other useful information.  If you have questions, you can PM me or ask on any of the threads.  We're a friendly group.