How do I fire a RemoteEvent and then kill the player in a script?

So I came across a problem in my game where if you shoot and player and kill them in your perspective there dead but on there screen there alive and have taken no damage.Then I searched on the internet and found a page on this topic but didn't really understand it because I didn't know how to do any of the stuff they were telling me to do.

So I was wondering if anyone could tell me how to do these things?

Here's the link to the link to the website page:

https://devforum.roblox.com/t/players-do-not-die-when-shot/177344

And here is the gun I am using:

https://web.roblox.com/library/1335008968/Pistol