Raspbian is an operating system built specifically to be used on your Raspberry Pi. It is based off Debian and comes installed with plenty of tools to monitor and code for your Raspberry Pi. This guide will show you how easy it is to install Raspbian (or Raspbian Lite) on your Raspberry Pi without a monitor (headless).
Pi-hole is a fantastic product for your home network and allows ad blocking at the network level. My install Pi-hole article will walk you through every thing you will need to do to install Pi-hole from scratch using a low power Raspberry Pi!