Correct. Multiply with an amplitude of 1 will yield values between roughly 0 and the existing altitude.
For the most part, you shouldn't need to mess with the things in the left-hand column (H, Lacunarity, and so on). Those are the parameters for the ancient Musgrave fractals as described in Textures and Modeling: A Procedural Approach. Some internet searching should get you appropriate information if you really want to play with them (Musgrave and Lacunarity will get you some good hits).
The right-hand column is probably more useful. Amplitude is the scaling for each point on the fractal. Displacement is the offset for each point on the fractal. XY Scale give the horizontal and vertical feature size for the fractal. XY Origin sets where on the plane the fractal is located (moving this will give the appearance of different fractals). Seed is the random number generator for making the fractal. Each one gives a different fractal if all other parameters are held the same.