A few questions on settings.. (Nikon D3100)

[arian29]

>AFS C or S ? what and why ?
>Whats metering ?
>How to focus on a subject then move the cam so place the subjet on the side without loosing the focus ?
>Pic saving quality Normal, smooth or what ? and why ?

 

[nac]

>How to focus on a subject then move the cam so place the subjet on the side without loosing the focus ?

This is how PnS cameras do. Try this...
Focus at the subject and press the shutter half way (keep it pressed half way), and compose the way you want and press the shutter fully.

Since it is a SLR, you may have dedicated button to lock the focus. Read your manual, it will clear your doubt.