What is required for a DM map?

[Interitus]

What is needed for a proper DM map? What entitites? what brushes?

Taking a look at the DM_lockdown map, there are a LOT of hint brushes, various nodraws, and all sorts of other stuff in there.

Being a n00b to half-life engine mapping, what does it all mean? what does it do and where do I know to put it?

 

[The Dark Elf]

nodraws stop them being drawn (like how the skybox texture used to be used a long time ago only works better now)

hint brushes just give hints to how it should be cut up into a bsp file. Makes things work more efficiently and stops things your not supposed to see from being calculated.