1. Navigate to the Inventory > Configuration> Attributes

2. Click on New

3. Fill in the details. You can define the different attributes that you want to apply to your products. In this example we will add Color. 

4.  You can add values in the Attribute Values section. To add a new Color click on Add a Line in Attribute Values 

5. Click on Save

You can also watch this video for reference: https://waoconnect.screencasthost.com/watch/c0eVoxVy7hN