The basic understanding of the blockchain needs to be gotten for a better understanding of what the blockchain is used for. In a basic language, the blockchain is like a record book, used to record cryptocurrency transactions and information, better called a ledger. The Blockchain is a technology for storing data in a way that makes, hacking and cheating difficult or impossible. A blockchain is simply a network of computer systems that maintains duplicate copies of all transactions in a digital ledger that is disseminated throughout the network for everyone to see.
The best ways you can earn from it is to learn about the uses, the commonest of it is in cryptocurrency related transactions, you can make money from crypto by learning how you can trade it using the trading strategies that work.
Also be security conscious and take necessary caution while trading, learn well before reading and do proper research and choose what works best for you.

A blockchain network can be developed in different ways. This network can be public, private, permissioned or even constructed by a group of people (known as a consortium).

This article helped me understand the different types and their respective pros/cons - https://blog.bitmama.io/what-are-blockchain-networks-and-how-can-we-use-them/