First, read your statement of coverage carefully...down to the letter. If it doesn't specifically say it will pay or reimburse for something, know that it won't. Secondly, you'll need original recepts for anything you spend and expect request reimbursement for. You'll also need a confirmation from the airline that the flight was cancelled and for what reason.
We had the Travel Guard coverage through HGVC and underwitten by Nationwide for our trip to Hawaii last spring break when ATA delayed our flight by 11 hours. On first read it looked like they'd give us money for our time on the ground and reimburse the lost HGVC points for the night we didn't get to use. In the end though, upon careful examination and lots of documentation, the insurance only paid to reimburse our out of pocket while we were at the airport for 11 hours, which amounted to about $50 in fast food charges.
They would have covered a night in a hotel except ATA at the time gave us vouchers which covered our stay at the airport hotel that night until our connection flight could be made the next day.
We definetly didn't get what I thought I had quickly read was covered, but that was mostly my mistake.
Again, read the statement of coverage very carefully when deciding if you want the insurance. For big $ trips, I generally want it as you never know what may happen.
and enjoy Hawaii.