Set a session variable for a logged in user

I am creating a log in for a patient so they can access information regarding prescriptions etc for a project - (isnt going live)

So I have my patients already created with useame and password and they are linked to their medication through a link table. The log in works and acknowledges that a correct user from the database has logged in - however I want them to be able to access their own details once they are logged in

Imports System.Data.SqlClient
Imports System.Data

Partial Class Pages_Login
Inherits System.Web.UI.Page


Protected Sub btnlogin_Click(sender As Object, e As EventArgs) Handles btnlogin.Click

    Dim patientNo As String
    Dim password As String
    Dim bAuthethicated As Boolean
    patientNo = txtuser.Text
    password = txtpassword.Text
    bAuthethicated = CheckUser(patientNo, password)

    If bAuthethicated Then
        lblresult.Text() = "correct"


    Else
        lblresult.Text() = "Incorrect Student Number and/or Password"


    End If

End Sub


 Public Function CheckUser(patientNo As String, password As String) As Integer
    Dim cmdstring As String = "SELECT * FROM Patient  Where Useame=@PATIENTNO AND Password=@PASSWORD"
    Dim found = 0
    Using co As New SqlCoection("Data Source=(LocalDB)v11.0;AttachDbFilename=C:UsersLauraFinal_projApp_Datasurgerydb.mdf;Integrated Security=True;Coect Timeout=30")

        Dim cmd = New SqlCommand(cmdstring, co)
        cmd.Parameters.Add("@PATIENTNO", SqlDbType.NChar).Value = patientNo
        cmd.Parameters.Add("@PASSWORD", SqlDbType.NChar).Value = password   

      co.Open()



        Dim reader = cmd.ExecuteReader()

        While reader.Read()
            Session("PatientId") = CInt(reader.Item("PatientId"))
            found = CInt(reader.Item("PatientId"))
        End While

        reader.Close()
    End Using
    Retu (found)
End Function

End Class

I have notes with the example of a student (mines is patient) however I dont know how to apply this.

Example of session

Try

 Dim co As SqlCoection
 Dim cmdAs SqlCommand

 Dim cmdstring As String = "SELECT * FROM student WHERE "studentnum =  @STUDENTNUM"
   co = New SqlCoection("Data Source=.SQLEXPRESS;  AttachDbFilename=|DataDirectory|University.mdf;Integrated
   Security=True;UserInstance=True")

    cmd= NewSqlCommand(cmdstring, co)

    cmd.Parameters.Add("@STUDENTNUM", SqlDbType.Char).Value =  Session("StudID")
     co.Open()

  Dim myReader As SqlDataReader

   myReader= cmd.ExecuteReader(CommandBehavior.CloseCoection)

   GridView1.DataSource = myReader
   GridView1.DataBind()

    co.Close()
   Catch ex As Exception
   Response.Write("An error has occurred")

End Try