autonomous timing

[seanl]

how can i program the robot to do something for a amount of time because i want to program autonomous to just go toward the rack.
so far i got this but im not sure how the while loops are going to work
while(autocounter2<=10)
{
pwm01=200;
pwm02=254;
autocounter2=autocounter2++;
}
if(autocounter2==2)
{
while(autocounter<=50)
{
pwm01=254;
pwm02=254;
autocounter=autocounter++;
}
}