How to create custom login without ASP Login Control

Dear Code masters,

I have an application that have completed, the application have three folders

1. the root folder

2. Admin folder

3. Staff folder

in database i have created a table called tbl_User with the following fields

1. id

2. username

3. password

4. role

5. email

the id is the key field and it is auto incrementing, the role have three roles as follows

1. Admin

2. HR

3. Staff

the idea is, i want user with Admin and HR roles to be able to access all part of the folders above but user with staff role should only access Staff folder.

i don't want to use ASP Login Controls, would like to code it along with the tbl_user table from my database.

can any one assist in sharing how to achieve this?

thank you all