You may create a new job by selecting selecting Create New Job displayed displayed on the top right of your job list grid.
Once selected, you can enter a a job name, a brief brief job description and and then select the system system entity. For most installations there will only be a single entity selection, however if Interrogate has been configured to accept multiple entities, you may see more than one choice available.
Click the arrow button or or Enter on on your keyboard.
A new job will automatically be created and you will see an empty search grid.