There is a wooden bridge leading out of the small parking lot -- easy to find. Take up positions along the bridge. Sunrise will be about 6:20AM, so try to be there well before 6. Bring a tripod and remote shutter release if you have one -- or use your camera's self-timer.
Once the sun is up, you may want to shoot the morning surfers from the Huntington Beach pier (PCH and Main Street). There is an IHOP on Main and Olive (two blocks from the pier), as well as a Starbucks.
There is also a local, family run, side-walk restaurant, on Main Street -- the Sugar Shack -- and a Coffee Bean and Tea Leaf two blocks from the pier.
If breakfast isn't in your plans, you can take an easy hike around the lagoon and loop back to the parking lot.