Potassium sorbate/Potassium metabisulfite question

ok i picked up the Potassium sorbate and Potassium metabisulfite now how long do i need to let this stuff sit in the carboy wiht the cider befor i can transfer to the keg?

also do when i add the stuff to the cider, do i need to shake it up?

also i have the cider in my keggerator to cold crash it, sense there is no beer in it(yes i know a very sad thing had to settle for buying beer at the store)does the stuff work when the cider is cold or shoudl i warm it up for best effect of kill off all yeast?

You only need to do that if you plan to back sweeten (with sugar that will ferment). If you're not going to add any more sugars that can ferment, then you don't need to dose it. Especially if you'll be serving it off of tap.

im going to be adding sugar to the cider.. im going to be adding a can of condense apple juice to the hard cider ..maybe two cans depending on how much i needs to be sweetened up..

so could someone answer my questions please?

From what I recall, you dose with the pot. meta for 12-24 hours (maybe longer, but no more than 48) and then the sorbate when bottling/kegging.

Still, if you're going to serve from keg (not bottling any) you shouldn't need the sorbate at all. Actually, you could probably cold crash it for a while, then keg, and still back-sweeten without needing to treat with chemicals at all. Or filter it from one keg to the serving one and also not need to hit it with chemicals.

I'll be carbonating my hard cider in bottles, for this batch.

If you are back sweetening, you can add it all at the same time. Stir gently, but well. I would do it at room temperature and wait 3-4 days before bottling/kegging to make sure there is no additional fermentation.

If I were kegging it and it would always be refridgerated I would not add the sorbate or the bisulfite at all.