The collet die,will remove the old primer and size the neck,of the case.Bullet seating is a different die.
Depending on what gun you are using,you may not have to crimp the bullet in.Lever actions and other tube fed guns,you crimp. If you care to crimp them,Lee's factory crimp die is excellent. It will not mess up your cases,if they are not all the same length.
Here are the stepes,as i do them:
Fire new shell cases[in my gun].
Set up collet in the press and run cases through.
Check cases for flaws.
Clean primer hole and replace primer.
Charge with powder.
Set up bullet seater die and set bullets.
[If I am going to crimp them],I set up my Lee factory crimper die and run them through and place these in a marked container.This has a record of the powder,the amount,the bullet,the C.O.L.,date and how many times these were loaded,on it.<img src=icon_smile_approve.gif border=0 align=middle>

Mounting Man/in PA.