fireball85

Hey all im new here and new to pyros in all. I need to know how to use some maroons (small) appear as if they are blowing a small crater. The effect i would like is one i have been told could be achieved by digging a small hole with the marroon placed in, then covering with a bit of compost. This way when it is detonated the compost goes flying everywhere much like when a shell hits the ground, but being soft it will not hurt anyone.
I also want to know how i could create a cloud of smoke that would appear as if something had been blown up.

Thanks

P.S. this is for a cadet exercise and we do not have a huge budget to spend on pyros