srry is correct, you'll need to enter the relative path and name of the model.
Note that both func_furniture and func_monster have a bounding box that the player collides with, and if I remember correctly, both can be blown to gibs with explosives. In most cases that collision box is too large or too small for the actual model, so I used the cycler entity as a workaround, though it's a bit harder to use. Using models in HL is a bit hacky, allas.