If you have tried something and that didn't work then we could have help if you had posted the error or issue details. But as it seems, you are yet to try it, we only can suggest some tutorials or articles which you could have find if searched in google with proper keywords.
Here is an article from CodeProject-
Using PostgreSQL with Entity Framework in ASP.NET MVC[
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and another article more focused on EntityFramework with PostgreSQL-
Rob Conery | Using Entity Framework 6 with PostgreSQL[
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Get started with these, try to download the sample project as suggested in the article and see if things goes as you want. In case of any difficulties, please let me know.
Hope, it helps :)