How?

For the simple case, on web: Click the time I want to put in an event for, type in a name, click "Create Event". Even if somehow you managed to simplify further "I want to do something at this time - I want it to be named this - I am done" I'm not sure the world benefits from that being easier.

For the more complicated case... Really? I admit I haven't played with it on Android in some time, but is it really easier to, say, create a new event, invite 4 people, add a conference room, select a time that works for everyone, make it repeat Monday, Wednesday and Friday, with a reminder 10m before and 20m before? Because if so I'm honestly surprised - that they even offer all that functionality at all, let alone that it's easier on mobile.