poor u... i'll use no large letters in this post to make it easy on your eyes
u did not see any objectives? strange...
well to insert a wall that explodes from the explosion do:
1) create a wall and prepare it like
3. something to blow up ( make it a script_object, give it '#set 1' and 'targetname exploder' )
2) create an exploded version of the wall like
7. something left after the explosion? ( make it a script_object, give it '#set 1' and 'targetname explodersmashed' )
that should do it... the 'exploder' object will be replaced by the 'explodersmashed' object when the bomb blows...
be shure to see to it that all brushes have the right class ( mostly script_object's... if not correct, the result is unpredictable )