Newcomer to planted tanks.

[benga]

So I am new to all of this, I have a 20 Gallon tank that my turtles no longer need because they've been upgraded. So with that 20 Gallon i want to make a planted tank.

I don't know what substrate to use, i was reading though a few threads and they were talking about top soil and clay and all this stuff.
Is it not enough to just use something like this (http://www.amazon.com/Hagen-12691-Fl...rium+substrate)
and plant your plants in it?

can someone show me a guide as to what i need in priorities?

I would love it if you guys could give me a list of things i need substrate wise through amazon.

So far i have
(http://www.amazon.com/Hagen-12691-Fl...rium+substrate)
http://www.amazon.com/CaribSea-Eco-C...s=Eco-Complete