When adding a new starter to the system or creating an additional employment to an existing employee, one of the steps in the process is selecting the post you are adding the employee in.
If the post you've selected does not have an approver set up for new employments you will get the message 'Approvers not set'.
This signals that you will need to set an approver on the post, which can be done by following the steps below:
Click Admin Menu, then Post Setup.
Search for the post you need to add the employee in and click on it.
Click Approval, then Approvers.
Click Edit in the Reports To (Line Manager) area.
Click Select Post, then Change.
Select the post that needs to be the line manager for this post.
Click Save.
Scroll down to New Employments and click Edit.
Enable the Approval Required toggle if it's not already enabled.
Make sure an approver is selected and click Save.
Once the above has been completed, go back to adding the new employment and you will be able to proceed without any errors.