guys im new to mapping and i need help........i dont get how to use the blender......

In all seriousness, Blender isn't usually used for mapping. Generally, people use GTK Radiant, and possibly include models/geometry created in Blender. You can find it here.

LOL..
I guess he means the 3d modelling software but sadly i have no clue about it and from what i gathered from others you should rather use radiant for mapping. Blender is fine for creating models though.. Just wait for our experts to read and respond. Or you ask the almighty expert: http://www.google.com/search?q=3D+blender+help

If your asking how to use Blender i suggest you work yourself through these tutorials:
http://en.wikibooks.org/wiki/Blender_3D:_Noob_to_Pro

Note that learning a modeling program needs a lot of time if you haven't used any similar program before, so follow these tutorials attantively.

If your asking how to make maps for Nexuiz, you should learn how to use GtkRadiant, which is the editor used to make maps for Nexuiz and other games like Quake3.
To get GtkRadiant working see this thread: http://alientrap.org/forum/viewtopic.php?t=10

To start mapping search for tutorials using google or this thread: http://alientrap.org/forum/viewtopic.php?t=9

also if you go into the IRC channel I'm sure someone will walk you through the program(s). Radiant is not hard to learn but it can be a pain to use from time to time.