Thank you for reaching and I can try and help you here.
Based on the steps mentioned in your question above. I am able to see the Service Endpoint Section under Settings->Subnet->default->ServiceEndpoints. Please refer the image below.
In the Services dropdown above, you can select the Microsoft.Storage.
If you are not able to see these details. Can you please share a similar screenshot of the Vnet? and a link for the skills guided project will be helpful.