Thank you abjaye. The terrain height script is a very good basic script for NCL tutorial. In my case, wrf.out file for PM2.5 and PM10 has time step, level and coordinates attributes. I have preference for gsn_csm scripts. This is a sample of the script I finally used in case anyone is interested. The script has two plots - data on native and non-native grid.
;----------------------------------------------------------------------
; - Plotting WRF data on native grid
; - Plotting WRF data on non-native grid
;----------------------------------------------------------------------
; These files are loaded by default in NCL V6.2.0 and newer
; load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
; load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
; load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRF_contributed.ncl"
;----------------------------------------------------------------------
begin
;---Add data file and read variables
; f = addfile("wrfout_d01_2003-07-15_00_00_00.nc","r")
dirp = "/root/Build_WRF/WRFV3/test/em_real/"
filp = "wrfout_d01_2012-09-10_00:00:00.nc"
pthp = dirp + filp
f = addfile(pthp,"r") ; new input file
PM25 = f->PM2_5_DRY ; (Time, level, south_north, west_east )
printVarSummary(PM25)
level = 1
;---Open workstation and set resources for first contour plot
wks = gsn_open_wks("x11" ,"dataonmap") ; ps,pdf,x11,ncgm,eps
res1 = True
res1@gsnMaximize = True ; maximize size
res1@cnFillOn = True ; color plot desired
res1@cnFillPalette = "WhiteBlueGreenYellowRed"
res1@cnLinesOn = False ; turn off contour lines
res1@cnLineLabelsOn = False ; turn off contour labels
res1@cnLevelSpacingF = 1.
res1@gsnAddCyclic = False ; turn off longitude cyclic point
res1@lbOrientation = "Vertical"
res1@lbLabelFontHeightF = 0.015
res1@tiMainString = "WRF data on native grid"
res1@mpDataBaseVersion = "MediumRes"
;---Set map projection based on global attributes on file
res1 = wrf_map_resources(f, res1)
; res1@tfDoNDCOverlay = True ; old method
res1@tfDoNDCOverlay = "NDCViewport"
;---Draw first contour plot
plot = gsn_csm_contour_map(wks,PM25(24,level,:,

,res1)
;---Set resources for second contour plot
PM25@lat2d = f->XLAT(0,:,

; need for map limits
PM25@lon2d = f->XLONG(0,:,
res2 = True
res2@gsnMaximize = True ; maximize size
res2@cnFillOn = True ; color plot desired
res2@cnFillPalette = "WhiteBlueGreenYellowRed"
res2@cnLinesOn = False ; turn off contour lines
res2@cnLineLabelsOn = False ; turn off contour labels
res2@cnLevelSpacingF = 1.
res2@gsnAddCyclic = False ; turn off longitude cyclic point
res2@lbOrientation = "Vertical"
res2@lbLabelFontHeightF = 0.015
res2@mpMinLatF = min(PM25@lat2d)
res2@mpMaxLatF = max(PM25@lat2d)
res2@mpMinLonF = min(PM25@lon2d)
res2@mpMaxLonF = max(PM25@lon2d)
res2@tiMainString = "WRF data on C.E. grid"
res2@pmTitleZone = 4
res2@mpDataBaseVersion = "MediumRes"
res2@pmTickMarkDisplayMode = "Always" ; nicer tickmarks
;---Draw second contour plot
plot = gsn_csm_contour_map(wks,PM25(24,level,:,

,res2)
end