Players make saving throws when they are subject to effects that allow them. They roll a
d20 and add their bonus.
XPTS are split among the party. The
DM can award more XPTS for things other than killing monsters.
Download these PDFs to get more answers :http://
dnd.wizards.com/articles/features/basicrules
They are cut down versions of the printed books. Also grab the SRD here
http://dnd.wizards.com/articles/features/systems-reference-document-srd
Most important thing for a
DM to know: The players are NOT the
DM's opponents. The game should never be
DM versus Players. Second most importantly, say Yes a lot to player questions-- except those asking for undeserved shinies