Many visitors land on this blog while searching for tips on how to build a court.
The best resource so far is on Petanque.org: here's the direct link to their building archives. You'll see some examples, in different locations. The above picture is of a gorgeous court in Hollywood, CA.
Make sure to read Ray Ager's post of Sept 2002, titled "A campaign for real petanque terrains". He is absolutely right that a plain rectangle with a smooth surface is not a must. An irregular shape, fitting in your natural surroundings, with some trees, bumps and dimples here and there is more natural, more challenging, and improves your skills. That's also why he uses the term "terrain", as opposed to "court".
Of course, everything depends on the space you have available.
The simplest way to start is by asking your local building materials supplier, quarry or contractor how they build a crushed stone driveway in your area. Stone types may differ from state to state, but the principle remains the same: if a car can drive on it, and the top layer is a mix from fine particles up to 1/4 inch, it works perfectly for petanque. In some places that's called "1/4 inch minus" or simply "screenings". The typical term in Provence is "clapicette", or "du zéro/six" meaning anything between 0 and 6 mm: same thing.
And don't forget to start with a weed barrier. It's cheap and will save you hours of pulling weeds.