2010 linq to sql

I am workin to setup a new C# asp.net 2010 webforms page in an existing website. When I do an add items to an existing file and click on linq to sql, the designer shows up. Then I drag some tables onto the designer surface and the tables show up. However, I do not see the schema. Basically the desinger does not know how the tables are related to each other.

Thus I am assuming that I will not be able to create a data context object? (The other dbml files in the solution are the same way.)

Thus can you tell me and/or refer me to a reference I can use so I can work with a new data context object? Are there work arounds for this problem?