How to dismiss a notification on iphone? (and not snooze it or edit it)

Hi, I get notifications from my calendar app on the iphone (calendar events are synced to the iphone calendar, McBook calendar, ipad calendar) that I cannot dismiss. When I click the notification it takes me to "edit event", I can snooze it, but I cannot "accept" or "dismiss" them.

Most of the cases everything I need, is to know about it, so I need the notification to show up. Once I see it - it's ok, I don't need to snooze it or edit it. It's done and I want to forget about it (I still want it to show as an event in the past though).

How do I do that?

As a side information (not a problem really) the same event (I already participated in, with my iphone) shows up as soon as I turn on my laptop. It's in the past, I was there, I don't need to be reminded.

On my laptop I can "close" the notification with the "x" sign. There is no "x" sign on iphone...

Is there any "user guide" for notifications out there? (I haven't found it on the web, but maybe I didn't use the right wording...) I can't get the idea what those terms are, "banners", "badges" etc.

Furthermore - every now and then the iOS asks me if I really want to keep something "time sensitive".

Why does it keep asking me something I've chosen to set a while ago?

I bought this iphone two months ago and it is still fighting for my attention asking me configuration questions, I've already answered.