Someone please help me to add user on already developed telegram bot?

i have created a basic telegram bot? now i want to add members into the bot? how can i do that?

Have you followed the instructions here? If it is not what you need, give more details.

i have created a telegram bot. but now i want to add members into it. but i had created a group and added my bot into it as administrator and worked upon it. but now i want to set a telegram bot, where students needed to access it through, but i need to set username and password into it