A basic altar will have a representation of the 4 elements, representation of God, Goddess or both, a pentacle, and something to hold water.
When you are starting out, you will not need a wand or athame (ceremonial knife) if you don't want to or can't use one.
For your representations of the elements, you could use (there are other ways to represent the elements):
- Some salt or dirt for Earth
- A small bowl of water or a shell for Water
- A red candle for fire
- A censer (incense holder) with an incense or a feather for Air.
For your representation of the God & Goddess, you could use a silver candle and a gold candle, or statuettes, even one of the Virgin Mary for the Goddess.
You can make your own pentacle with salt dough (you get to make it and paint it yourself, this will make it most personalized and thus more powerful) or you could buy one at any occult store.
For the altar itself, you can use a permanent, or impermanent one. You can even use a top of a dresser. Whatever you use, if you choose an altar cloth, make sure you are careful with candles nearby.