If you are just reinstalling sim, you don't have to do anything related to the activation. The above procedure is valid ONLY if you are reinstalling Windows or changing a major hardware component like the mainboard or the CPU or the boot drive.
And, it's not even "needed", because you have 6 activation for each order so, you Deactivate only to recover one and don't consume a new one when you reinstall Windows or upgrade hardware. But if you don't Deactivate, nothing will happen: it will just take a new activation from your pool of 6.
And, even if you consumed ALL you 6 activations, it's not even certain you'll have trouble reactivating (again, ONLY when you reinstall Windows or upgrade hardware ), because if your last activation has been obtained more than 90 days earlier, a new one will be granted even if you already consumed all your available 6.
Activate the products but how
With the "Register Serial" option from the Addon Manager menu, same as you did when you purchased it. But, again, ONLY when you reinstall Windows or upgrade hardware.
The activation is NOT stored anywhere in the sim. It's in the Windows registry.