Once you have finished with a job, which means you have either hired the candidate, or decided not to hire for the job any longer, you should 'Archive' it. 

This removes it from your public jobs portal and moves it to the 'Archived Jobs' section at the bottom of your 'Manage Jobs' page. 

To archive a job, browse to the navigation on the left hand side of your screen and select 'Manage Jobs' under the 'Jobs' section.

Locate the job you wish to archive and click the three dots to the right of it. Then, click 'Archive':

You job is now moved to the 'Archived Jobs' section at the bottom of the page and the colour to the left is changed to grey to indicate that it is archived.