scenery painting

so a few  weeks ago  we attended triples and bagged sum bargains  and i have been personally tasked with painting them.  the scenery in question is  trench and gun emplacements  now iv never painted scenery  before but im using it as a little break from the terrorgheist.

im wanting to create the look and feel of sand or dirt so what ill be doing is starting with

FOW - italian armour  is a nice bright yellow
next ill  brush  weathering powder  over it to deepen it
ill then affix this with a wash of devlan mud