Do you let the turntable spin when putting down record and attach the clamp.

Is there a difference between turning it off, stopping the motor, and stopping it spinning? On mine that is three different things. I could stop the platter spinning without stopping the motor, let the platter spin with the motor off, turn the whole thing off while the platter spins..... Only thing for sure is everything including turntables sounds worse after being turned off, so I would never do that. But I would bet that by off you mean stop not off. Or do you?

dc, historically I never turned the turntable off until the end of the session. The record weight I have used for decades was just placed on the spindle. It was not a clamp or screw on job. This has to change now as I have a new turntable coming which has vacuum clamping. I think I do not have a choice. You have to stop the turntable to change sides.

No, the platter is stopped when putting on or taking off a record. When the clamp is attached, the platter is turned slowly to make sure the clamp is tightened correctly. After playing a record, the arm is moved to the safe position, and the clamp is removed as the platter spins down.

I try to help the platter start up by gently spinning the platter.  I use reduced voltage to operate the table and it won't start at that low voltage without some help.  I use a Variostat to manage the voltage for ~ 70v operation (VPI motor).