Converting files with specific audio stream presets

[Gonzo]

Hi i'm trying to extract a specific audio stream with the video. What do I add or change on the fullscreen or wide screen mp4 output preset. I tried adding -map 0:3 just to figure out what it does. Is there any possibilities of adding an actual split video option  to divide the the video frame into 2 to 4 etc portions. This option would help me split say for example a security surveillance videos with 8 windows to 2 videos with 4 windows each.