For load the model use this code after level load:
Code:
model_zombie=ent_create("zombie.mdl",vector(0,0,0),NULL);

Replace zombie.mdl for the name of your model.
And vector(0,0,0) to the coords where you want to place your model.
For animate:
Code:
ent_animate(model_zombie,"jailslam",walk_percentage, ANM_CYCLE);

Replace jailslam for the name of your animation.

I hope this helps.
Cheers

Carlos Ribeiro aka Elektron
Check my blog: http://indiegamedeveloper71.wordpress.com/