SQL database error exception in c# using VS 2019 edition

I am new to C# database and I have been battling with this error for a few hours.
When I created the table, I used ctrl + s to save it but it saved like normal saving into My Documents which I think the problem comes from that.

Answer

SELECT * FROM [dbo].[Table]

You have to place your your table name in the place of table as mentioned below.

SELECT * FROM [dbo].[Customer]

Then do this:

In the upper-left corner of Table Designer, select Update.

In the Preview Database Updates dialog box, select Update Database.

The Customers table is created in the local database file.