This is the FAQ containg all the answers to your Debian Linux questions.
The Debian Linux FAQ contains a great amount of information pertaining to the Debian GNU/Linux distribution. https://drive.google.com/open?id=1XoEX7hJRkDbGYBHigWkd9TJE66bNILxuFvByFO9cbieufOPTcYQL0n7U_Hhr. Have a read of this and you will learn a great deal about setting up and using your new Debian system.
Securing Debian HOWTO. https://www.debian.org/doc/manuals/securing-debian-howto/. A guide to securing your Debian Linux system from attack.
Debian users` manuals. https://www.debian.org/doc/user-manuals. Comprehensive listing of Debian documentation.
How to get started with Debian. https://www.linux.com/learn/return-root-how-get-started-debian.
How to install an OpenVPN server on Debian Jessie. https://www.digitalocean.com/community/tutorials/how-to-set-up-an-openvpn-server-on-debian-8.