Sitebulb allows you to queue up a number of Audits, so they will run in succession as each one completes.
This allows you to get all your Audits set up and just leave Sitebulb to do it's stuff - perhaps overnight - so when can come back to your machine, everything is ready for you to get to work.
While you have an audit running go back to your projects page (click Projects in the top navigation) and start another audit. This audit will then get queued up and start after your current audit has finished.
Since one Audit is already running, you'll see a message telling you that the audit has been queued. Your original Audit will be running, and this message will simply confirm that you've got another one queued up. You can keep on adding new Audits and they will continue to queue up in this manner.
In order to find any queued Audits you may have, from the Projects page navigate to the 'Queued Audits' tab in the top navigation.