it's pretty easy to explain, really. you know what cryptography is right? it means in order to make use of the original text you need to unlock it by giving it a key which is another unique chain of text. the computer then takes the key and performs MATH along with the gibberish text to bring it back to a readable original. this is not much different than a cereal box decoder ring
well the thing that's great about these situations is if anyone changes something in the gibberish text, the resulting output when you decipher it will be gibberish too. that means people can't tamper with the coded stuff, unless they go through a lot of trouble to pretty much try every possible key to find the one that works with the MATH and produces a valid readable output
now with that background on cryptography you're set to understand blockchaining which basically takes the output of a cypher, and uses it to re-encode the next one, creating a chain. you still can't tamper with the new code without knowing the key, AND it's twice as hard to tamper with the previous link in the chain because there's two sets of MATH that you would have to power through to crack it
in this manner you can store data, like a money ledger safely and securely as long as you consistently have a network of workers adding more and more MATH on top of the chain. as long as the attacker doesn't have as much working power as you do adding more on top, he can't go backwards and undo your ledger entries and supply his own values
and that's pretty much the bare basics on what you need to know to get started in cryptocurrency!
Thanks for the explanation