Making coffee in a French press is much like making coffee using any other method. The only difference is how coarse the beans will be ground.
If you can find one, look for a "French press" style bean, which means that it is ground a little bit coarser than other beans, which might pass through the filter and give you little grainy bits at the bottom of your cup.
If you're grinding them yourself, they should be the texture of coarse sand. You should be able to see distinct pieces, but none no bigger than 1/4 of a centimeter at the very biggest. Add two tablespoons of coffee to your French press per cup of coffee you're making (2 cups=4 tbsp, 3 cups=6 tbsp, and so on)
Your water should be around 80 degrees Celsius, or just before boiling. Gently pour your water over the coffee, ensuring that every grain gets soaked, and let sit for five minutes. Gently press the top of the French press down, and you're done.