Anybody give a starter on how may I get information about users from my telegram bot. Imagine my bot in an admin user in my channel and I want to get my channel user list or
Telegram Bot doesn't keep anything about your users. You should save by yourself all users which communicate with your bot. For example, store their IDs in database.
In case of Channel - you can get this information from Channel's members list.
If you need to be notified - your bot should store users somewhere and check if user is a new one.