In order to add metafields to your products, blogs, customers etc. you need to create a schema.
To begin your schema start by clicking the Edit Schema button in the top navigation menu.
This page will list all of the objects that metafields can be applied to.
Adding a field
To add a metafield click the Add Field button of the object that you wish to have the metafeld.
A field will be created and you will need to enter the handle and select the type for the field.
The type that you choose sets what options you have when you create this metafield on an object.
Saving the Schema
To save simply click any of the Save buttons