I've been doing some digging on Bitcoin's "nLockTime" feature which allows anyone to "lock" BTC funds on the Blockchain for a specified time frame. This could prove to be useful for preserving BTC as a form of heritage, where funds will only be unlocked if a certain date (or condition) has passed. I've found some info about it on the official Bitcoin wiki site here. Most of the information is too technical which proves to be quite difficult to understand for the non-tech savvy user. Of course, I was able to understand most of it, but my friends who are not quite fond with Blockchain terminology have found out it to be quite complicated to understand.

What I want to know is how does the nLockTime feature on the BTC blockchain work in layman's terms (ELI5)? This way, I'll be able to clear some of my doubts to properly educate my non-tech savvy friends about it. Additionally, I'd like to ask how to do this with the Bitcoin Core wallet? I've been looking around the web, but have been unable to find a tutorial or guide that would walk me through on setting a BTC transaction that would be unlocked at a certain point in time.

Any help, suggestions or recommendations will be greatly appreciated. Thanks in advance.