There are many good trainers out there and I will post a link a list to some in a moment. Be advised that the chances of using the FIRST one long enough to put it on floats is slim but possible. I'd suggest concentrating on learning to fly off a proper field first and then move on most likely with the second plane. Water flying adds many complications.

Here's the link: http://www.rcuniverse.com/forum/m_4537845/tm.htm

And I also suggest joining a local club for excellent training and improving the lifespan of your plane and your enjoyment of the hobby. Plug your zip code into this link for clubs near you: http://www.modelaircraft.org/clubsearch.aspx

Good luck