How to play online?pc

First install the PC Origin client onto your PC, log into the PC origin client with your Origin account, purchase and downoad BF3.  Once downloaded double click the BF3 icon in your PC origin account and it will open and log you into Battlelog.  From there click the multiplayer tab at the top of the page, set your server browser filter settings and choose a server and join it by clicking the square with the triangle in it on the left hand side of the server name.