The first rule of float flying is to be sure you have access to a boat. (I've been looking forward to posting this picture.) The boat does not have to be fancy.

THe plane may trim differently when you add floats but don't expect to have to learn to fly all over again.

Takeoff: Point into the wind. Hold full up when you initially give it power. As soon as the tips of the floats rise, neutralize the elevator and let the plane climb up on the step. When it is going fast enough for takeoff, ease back on the stick and she'll fly off. Come to think of it it's almost exactly like takeoff in a taildragger.

Landing, line up FROM THEdownwind DIRECTION. Try to plan to land a little bit past you so the breeze will blow the plane toward you. Hold a little power until you are SURE you are over the water. I've been farther out than I thought and strained it thru the bushes more than once. Catching a shadow in your peripheral vision when the plane is coming over the bushes on the far bank helps. When you are close to the water you can gauge your altitude by watching for the reflection in the water surface. When the floats touch the reflection you are down.

Taxiing is the hardest thing and the part of float flying that is most different from wheeled flying.
If the motor is running: The plane will be moving.
If the motor is NOT running: The plane will be moving-but you can't control it.