I've been trying to understand the concept of bitcoin for a while now, especially its technical aspects, so I've been doing some personal research on my own, but I still find it difficult to comprehend some parts of it.
I learned during my research that a node is a computer on the blockchain network that sends and receives transactions with other nodes while also validating and storing those transactions and I also read that transactions on the blockchain are kept and encrypted within blocks and that a block's transactions needs to be verified in order for a new block to formed.
I need more explanation because I still don't understand how a node confirms a transaction and determines whether a block is valid, it seems too complicated.
I'll try to put it in simpler terms. The nodes in the Bitcoin network have been charged with verifying the validity of each new transaction before accepting it. To accomplish this, they check for things like the digital signature of the transaction and if any coins have previously been spent using highly complex mathematical calculations and encryption. We refer to this procedure as validation. The transaction is added to the blockchain and deemed "confirmed" if it successfully completes all validation checks. I hope this makes it more clear how nodes validate or confirm transactions on the block.