Once you’ve deployed a campaign, you cannot modify the groups associated with it. Your only option is to add employees to a group that’s already part of the campaign.
If you have a Static group connected to the campaign, simply add the employees to that group. Remember they’ll also receive training from any other campaigns using that same group.
If you only have Dynamic groups connected to the campaign, employees will only be added if they meet the group criteria. If your new employees don’t meet the group criteria, you’ll need to create a new static group for them. Duplicate the original campaign and connect the new static group to the duplicated campaign.