How to connect database into this project and then what are the steps are flowed

Simplest way:

using (SqlConnection con = new SqlConnection(strConnect))
    {
    con.Open();
    using (SqlDataAdapter da = new SqlDataAdapter("SELECT MyColumn1, MyColumn2 FROM myTable WHERE mySearchColumn = @SEARCH", con))
        {
        da.SelectCommand.Parameters.AddWithValue("@SEARCH", myTextBox.Text);
        DataTable dt = new DataTable();
        da.Fill(dt);
        // Use the datatable data.
        }
    }

Other than that, we can't say - we don't even know what environment your project is going to run in, much less what it will do.
But...if this is your final year project, then you should know how to use a DB in your code already, unless you haven't paid any attention during the course so far...