give it some if statements like
psuedocode
if myobject < monster position(for both x and z) + distance
point monster, myobject position
move monster,distance
endif
but basically the monster moves in the main loop
think about being your monster and what code it would take to move him toward your character
if objects are in the way, what will your monster do, how to move around them
maybe to duck if you shoot at him or a bullet is close to him
but keep it simple until you get him movin around
My advice is free -
unfortunately you get what you pay for (-: