I'm trying to follow this tutorial https://docs.nopcommerce.com/display/en/Plugin+with+data+access
for creating a plugin with data access.
I managed to build my first class okay but i've ran into an error on the Entity Framework mapping class.
I've copied the content from the tutorial, but it complained about missing references, so I added Nop.Data.Mapping
as it suggested.
But now I get the error Add reference to 'EntityFramework...'
as seen below.
How do I go about adding a reference to this? When I click add reference a box appears as below
If anyone could point me in the right direction that would be great.