Passing Variables from Workflow into Powershell Script

So we have a workflow that we set up to stop the helpdesk from adding users to a group who are members of another group.  The users cannot be in both groups at the same time, these are 365 licensing groups.

What we are trying to accomplish is having a powershell script run that will remove the user they are trying to add to the group, from the other group (that they shouldnt be in).

The powershell script is simple enough, but I cannot find really any good documentation on how to pass a variable from the workflow into the script.  The variable would be the user the heldpesk is trying to add to the group, that needs to get passed to the script so the script can remove that user from the other group which they shouldn't be in.  Can anyone assist?  Thank you.