When launching from a dock or a beach you should be aware that this is a very vulnerable time.
The seaplane is slow, has limited control and maneuverability due to its slow speed, and you are likely in a confined area. Be aware you have no brakes once the engine is running, and if the engine stops running, you will be at the mercy of the wind and how fast you can paddle to keep the seaplane clear of obstacles.
YOU MUST IDENTIFY ALL OBSTACLES BEFORE LEAVING THE DOCK OR BEACH. This means locate your obstacles before you launch, and have a plan to maneuver around them. You should also have a plan based on the wind and current of what to do if the engine does not start correctly (it may shut down on you or you may shut it down for lack of oil pressure, rough running, etc.). To sum it up, HAVE A PLAN (or five).
You can self-launch, or have a friend help. Having an extra person makes a big difference (especially on a dock).
Launching with a friend is much the same. One person can hold onto the strut while the other starts the engine (of course use caution with anyone near the aircraft with the engine running).
A little common sense goes a long way here. You will have dragged or lifted the back of the floats onto the sand when you beached. You may have even turned into the wind if it was strong enough, and allowed the airplane to drift back to the beach. It shouldn’t take much power to get the airplane moving, and using lots of throttle here can be hard on your propeller. Be conscious of tide, wind, and bottom conditions when beaching or launching from a beach. Rocks, logs, pointy sticks, etc. can do a lot of damage to your very expensive floats (or hull).