Controlling a loaded schematic
The control GUI has a few things you can control and view.
The schematic can be moved with the buttons on the middle of the screen. You can even input the exact coordinates by manually typing them in.
The bottom right corner of the screen allows you to hide/show the schematic and/or move it to your player. The rotation button will rotate the schematic along the Y axis in a clockwise pattern when looking down.
The printer is currently the only way to place the blocks into the world somewhat automatically. It still requires some player interaction, but the blocks will be automatically placed in a 3 block radius around the player.
The layer control allows you to switch between layer and complete mode. When in layer mode you can switch the layer using the control just bellow the toggle button or alternatively with key bindings (they are not bound by default!).
by clicking the Materials button a new GUI will pop up that will show all the required materials to build the currently loaded schematic. If you're in layer mode only the blocks on the currently selected layer will be displayed.
In 1.8 the ability to sort and export the material list was added. The list is exported into the .minecraft/dumps/ directory.