This post might be interesting and helpful for you if you're new to cryptos and need some tips and support to establish. But maybe some facts are new to you even if you're not a newcomer :) The most important and first step is to understand the basics of this whole allegedly super complex topic. In the following I will explain the term „Blockchain“.
At first you should know the concept of Blockchain which is the reason why Bitcoin was able to arise after all. The idea behind this system is the decentralization of transactions. That means that there is no single responsible institution reviewing the transactions taking place but many different comparing their data and confirming the transactions. This task is accomplished by miners which replace the banks what allows the users to not being controlled by banks anymore and staying completely anonymous. The longer a transactions dates back the safer it gets because more and more confirmed transactions followed after them - lining up in the blockCHAIN. So if someone wants to manipulate a fulfilled transaction he would have to dissolve the whole already checked and solid chain of transactions. That’s almost impossible and would be very complicated because - of course - it would attract attention to the miners immediately when the data don’t match anymore. Due to this Blockchain transactions provide a super high security level.
Please let me know if this post was helpful and which topics or terms you would like to understand better. I’d love to write more explanations like this and if you prefer them in German let me know, too! :)