Basic blockchain questions from a beginner

Helllo community

I've been aware of crypto technology and blockchain but I have only been researching the specifics since recently. So far I think I've got a very basic understanding of how blockchain works:

- A blockchain is operated by nodes and miners, nodes hold the ledger of everything that's ever happened in this blockchain, and there are many nodes out there supporting the blockchain. nodes are also used to verify transactions.

- A miner or a pool of miners are special nodes that generate the hash of each block, which is why they need a lot of computing power. Once the hash is generated, the block is then added to the blockchain, and the information in the block is forever in the record.

My questions are:

1. Is the above correct?
2. Since all the info is stored in nodes, and any transaction will need to get verified by nodes and processed by miners, how do one "access" a node? Is access one kinda like going on a website? you type in the address and information appears?
3. How to decide which node to access? is it decided by some sort of system?
4. You have to be "registered" to use a blockchain, right? and if it is an anonymous blockchain you are just a bunch of numbers and symbols? is the registration also a block?
5. How much does a block contain? a few bits? or a whole file?
6. There are some pretty sophisticated "apps" using blockchain, like the ones based on Ethereum. How are those Dapps accessing Ethereum? is it like current traditional apps accessing the internet?

I appreciate anyone responding, reading, or even just noticing this post. It's a lot of questions and I realize it must be difficult to explain something so complicated to someone so clueless, so thank you.