You now have the option to send a campaign immediately, without worrying about setting a time for it to go out. Here's how it works:

Go to Campaigns on your main dashboard and select new campaign:

Choose Immediate Timing and give your campaign a title. You can then define your target audience and select your action type.

Once you're happy with your action and messaging, select schedule. The following message will appear to inform you your campaign will go out immediately after activating it:

Select confirm schedule & save and then you're ready to activate! Double check you're happy with the target audience and actions and then click activate. Your campaign will go out immediately and you can track this through action reports.