Both options are managed via the OPTIONS / SIZES tab when editing a product.
When viewing the product list screen in the CMS, each product with a product variation will have a Option Count Shortcut visible on the product. Clicking this will take you quickly to the Options / Sizes area.
You can also navigate to Options / Sizes area via the OPTIONS / SIZES tab at the top of the or the Manage Options button at the base of the description area.
Once on the product variation screen your existing variations will be listed. You can edit edit the values, add new ones or delete via the red X icon as indicated.
Product options that are not configured using the Product Variations option, can be edited via the MANAGE COLOURS, MANAGE SIZES, and MANAGE STYLES buttons.
You can quickly view the current options available by clicking a dropdown available for each (See Screenshot below)
If you have additonal customisation questions these are managed at the bottom of the OPTIONS / SIZES page.