As you'd expect, the Ocado skill focuses mainly on getting the right products in your basket. But be aware: it's currently not capable of starting a new order, it can only add items to an existing one. A simple "Alexa, ask Ocado to add milk" will drop fresh dairy into your basket, while "Alexa, ask Ocado what's in season" can deliver some much needed cooking inspiration. The app also provides the ability to edit orders, check whether a delivery on time and query what you've already added.
For Ocado, the Alexa skill is merely an extension of its existing apps, which are already available on iOS, watchOS and Android. While it might be the first to provide a dedicated Alexa offering, Tesco was the first to trial voice ordering on the Amazon Echo, thanks to its clever IFTTT recipes.
While you won't be able to see what you're ordering, the company says it'll use its understanding of customer preferences and previous orders to ensure it suggests the most appropriate items -- at least in theory.