How do u make say a 88flak model so no man can go through it... basically so its solid?

clipping a model has been discussed many times but heres a quick rudown.

place the model where you want it. then draw some brushes that are the same shape as the model to clip it. turn those models into a func_wall set "RenderFX: Addatvie or Texture" "FXAmmount: 0". texture the func_wall with an approratie texture for an 88 you would want metal so you would us cr_matmetal. compile and you shouldnt see the brush but it will be clipped and have the right texture FX.

if you dont want to clip the model search for the model zoo by waldo, theres a post in the forums.

Search for model_zoo

Using the latest version of hammer with model support really helps.