First, you must convert the Requisition into a job. You can read how to do this here.
Clicking the Convert to Job button opens the Add Job wizard, with a few modifications - allowing you to set the Approvers that the position will need to be approved by before it goes live on the website and you can start collecting applicants.
The job will be set to Draft. You cannot change this until the job has been approved by all Approvers.
The Add Job Wizard will give you an extra step, allowing you to choose the Approval Process set up by your Administrators.
Choose the appropriate Approval Process, and a series will appear, allowing you to select who the job will be sent to for approval.
You can also set the date and time they are supposed to approve the job by, so that you can track their progress if they have not done it by the due date and time.
Once you have done this, continue setting the job information together so that when it is approved, you can easily change its status and set it on the website.
When you have clicked Finish at the end of the Wizard, a message will appear:
The Requisition has been set to Pending Approval, and the first approver you have marked in the queue (as above) has been sent an email to notify them to view the Requisition for Approval.