I'm totally new to this and I'm pretty clueless

I know it sounds really dumb, but I have problems with the tutorial. In step two, after adding the do_move_location function, I don't know what the "default move" is. I'm supposed to replace it with this:
# find close food
ant_dist = []
for food_loc in ants.food():
for ant_loc in ants.my_ants():
dist = ants.distance(ant_loc, food_loc)
ant_dist.append((dist, ant_loc, food_loc))
ant_dist.sort()
for dist, ant_loc, food_loc in ant_dist:
if food_loc not in targets and ant_loc not in targets.values():
do_move_location(ant_loc, food_loc)
and I tried it several times, but the ants behave different from the example in the tutorial.
Please help me...
yours, bazinga