1. It is symbolic, so it is up to you.
2. The home pentagram can be as simple as one drawn with chalk. For making pendants, you would have to consult with a jeweler or metal worker. Let me mention however, that such pendants are not necessary.
3. The altar, when charged with positive energy from prayer, meditation, ritual, etc. acts like a magnet or light that attracts more positive energy.
“Nothing is easier than self-deceit. For what each man wishes, that he also believes.” —Demosthenes
"Do not worry; cultivate the habit of being happy." —Samael Aun Weor