How to build a from tfs accessing to database folders

I have. 2 TFS folder for 2 different databases.A stored procedure is trying access a table in other database folder.when i try to build it to link 2 folders in TFS?

You need to add a reference in the project to the other database

Can you explain the steps how to to add reference .I searched in google didnt get any help.

See this link to get started: