How blockchains work
To start, let's look at a single block. A block is a collection of information and the data in this block could be anything. For cryptocurrencies like Bitcoin, it contains transaction information; who's sending, who's receiving, and the amount. Each block has limited storage, so they get linked to the end of the previous block once they're filled.
A blockchain is a string of these blocks. To create the chain, each block also contains its own unique hash and the hash of the previous block. We can think of the hash of a block as a fingerprint, a unique marker for identifying that block and the information it contains. The information is public for everyone to see, but it's very difficult to change the data once added inside of a blockchain.
If the information in a block changes, then the hash changes, and it's no longer the same block. Holding the hash of the previous block is what creates the chain, and it's also what makes them so secure. If someone tries to tamper with a block in the chain, that block will change, causing the hash to change - invalidating all blocks after it in the chain.
Hashing alone doesn't make it secure. Blockchains use mechanisms called Proof-of-work (PoW) or Proof-of-stake (PoS) to validate new blocks that are added. This validation ensures there is consensus among everyone using the blockchain. Everyone has to agree which blocks are valid and which aren't - invalid blocks get ignored.
Blockchains are often called smart contract platforms because complex financial contracts (or simple ones, like transferring money on someone's birthday every year) can be encoded into one of the blocks.
Running a protocol based on smart contracts gives us greater self-sovereignty since we no longer need to rely on a centralized entity, like a bank, to perform the same transaction. In our example of the recurring birthday money, we would need to pay ETH if the smart contract is on the Ethereum blockchain.
You don't have to become an expert, but take the time to familiarize yourself with how blockchains work. It will help you understand the risks of owning crypto so you can decide if it's right for you.
All you need are the basics if you decide to start owning coins, using DApps, and getting involved in the rest of the decentralized crypto world.