Here's a basic breakdown:

* Reactants: The substances that are being changed in a chemical reaction.

* Products: The substances that are formed as a result of the reaction.

The arrow in a chemical equation indicates the direction of the reaction, with the reactants on the left and the products on the right.

Example:

```

Reactants --> Products

2H₂ + O₂ --> 2H₂O

```

In this example, hydrogen (H₂) and oxygen (O₂) are the reactants, and water (H₂O) is the product.