I'm new and not very well informed so I want to know how a service like blockchain.info gathers its information? where does it get the data from of all the transactions? A node? if so does that mean anyone running a full node can monitor the whole blockchain via their local machine? How would you do this? Is there anyway I can monitor the blockchain that means all transactions without using a third party site like blockchain.info or any other block explorer?
1. Yes, it gathers it by running a node.
2. Yes, anyone running a full node can monitor it with software that understands the protocol.
3. Yes, run a full node and then use software to monitor the parts you wish to monitor.
In short, you can run a full node and then write your own or use open source block explorer type software. If you are looking for something out of the box, requiring no technical knowledge, that probably isn't out there right now.