You have to fill in a variable that counts up.

function play_animation()
{
var counter;
var anim_speed = 10;// fill in here the wished animation apeed
while(1)
{
ent_animate(me,"walk", counter ,ANM_CYCLE);thax, but wath is warez user

counter += anim_speed * timestep;
counter %= 100;// if the counter is higher than 100 it proceeds at zero
wait(1);
}
}

But, there is an example in the manual, too.