man_in_black_pajamas

i'm new to the forum and just have a few questions 1. when downloading mods I understand that .pbo files go in the addons folder, but I don't understand .rar files or the mirror thing. Also, when you download a new weapon does it come equipped on a certain soldier or does it appear in a weapons box. 2. where should I go as new guy to ask or find the answer to simple questions (like how do you use the seagull, or has anyone made the M2A3 bradley), with so many topics in the forum its a little daunting, and don't want to be asking questions in the wrong places, especially if the question has probably been asked. Thanks my name is reference to the movie the Big Lebowski