You have set up your WordPress Woocommerce store, you have added a few products and now you want to add attributes to the products, for example colour choices or a choice of different sizes.
Here is how you do it.
First click on Products from the admin menu and then click on Attributes from the Product drop down menu:
Woocommerce how to add attributes to the products

Once you click on the Attributes link this page comes up, follow the insytructions:

Woocommerce - adding colours to the Product

Once you have created a Product attribute, for example Colours, then you must add some colours (terms) to your Colour Attribute. You can see above there are two terms (colours) already added, Green and Red.

The next screen shows you how to add some more colours to the Colour attribute.

Woocommerce Attributes

Once you have created all your attributes you can now add them to your product. You do this by going to your product list, choose the product to add the attributes. Scroll down the product page until you find Product Data

Woocommerce Product Data

From the Attributes link under Product Data choose your Custom product attribute, in this case, colours. Then click the Add button. Then click in the Colours Value(s) and one after the other choose the colours (or other attributes) for this particular product. If you click in the box the colours (or other attributes) available will appear. You can also add new attributes by clicking on the “New” button to the right of the input box.

Adding attributes to Woocommerce WordPress

Lastly do not forget to UPDATE the Product Page.