Autoguiding allows you to take very long exposures, by using a second camera to "keep a lock" on a star. This closed-loop pointing adjustment keeps the stars accurately positioned on the main camera's sensor.
Autoguiding is however a fairly complex operation, as it is a dual-axis servo control system. Many mounts have mechanical shortcomings that make autoguider setup tricky. MaxIm DL includes tools and adjustments that help you tune the autoguiding process, such as the Tracking Error Graph.
Suggestions are also included in this manual for ways to overcome various mechanical limitations of your hardware. Please be sure to review the Autoguider Troubleshooting section.