How do I use a quartz crystal in an oscillator?

How can I get a quartz crystal to make square waves at 4.096MHz? So far I have the 4.096MHz quartz crystal and this schematic I saw:

Where can you find an amplifier with a single input and what voltage should I use?

Answer

You can make a Pierce Oscillator similar to that shown in your question:

The "single input amplifier" is usually a simple CMOS inverting gate, like the 74HC7404 (6 inverters in one package), SN74HC14D (single inverter) or similar.
Voltage can be something within the operating range of the IC, such as 5V. You may need to add a series resistor to limit the crystal drive (you need to check the crystal datasheet for manufacturer recommendations)

Here is a circuit with typical component values:

Note the series R mentioned above. The above came from this Fairchild App Note which goes into some detail on the design process.

You can only pull the frequency of a crystal oscillator a very small amount, so you will need a 4.096MHz crystal. Either that or you will need to use something else such as a PLL.