To assign users PIN numbers in IDManager, you can select multiple users by 'ctrl+click' (to select multiple accounts that aren't together in the list) or 'shift+click' (to select all users between the first user highlighted and the second) or 'ctrl+A' (to select all).
Once you have your users selected, go to Tools > Data Tools
Change the drop down to Update Pins shown: .
Select how many digits you want these pins to be, and if wanting to generate new PINs for all users tick the 'Overwrite existing pins'
Click the .
If Data Tools is not available in your IDManager, this will be due to how your licence is configured and may need to be modified by the BioStore Support team, give us a ring if this is needed.