Welcome to the forum :)
There are two different events for switching layouts, not really sure why. But anyway, one of them is where you have to type the name of the layout you want to go to, and the other you just select it in a drop down. Why you wouldn't just use the drop down always im not sure, as it automatically updates if you change the name of the layout anyway, where the other one doesn't. But try to use that one instead.
Using a new event sheet for every layout, is not a bad idea. As your project grows keeping track of things can be a huge problem, if you throw all the events in one sheet, you will very quickly start to loose track of whats going on. Besides that you can just include event sheets into layouts.
Some tips for you, as I also started out just throwing everything into one event sheet, which costed some projects and some hair :D
Make 1 event sheet named the same as layout, and keep this as the standard. Even though you might not actually add anything to it, but then you have it in case it suddenly makes sense to use it. If you need something from the other events sheets just include them.
Make event sheets that take care of specific things in your game, for instant:
And just include them in the layout where you need them.
If you use functions, never add them to the same event sheet where you have actually events, like "on Mouse", "Key down", "Every 1 sec" etc.
But put them in there own event sheet, and again just include them where you need them.
So your event sheet layout might look like something like this:
The reason for this, is that functions will never run unless called. So if you add them to the same event sheet as the actual events are, and then include it. Suddenly you might experience weird errors. Because some of these events triggers because you accidently forgot to take something into account.
In general I would also suggest that you start getting used to use functions as much as possible. As it will speed up making the game. But also make the game a lot easier to troubleshoot. As a function is very easy to test....."You put something in, so you expect something to come out again". And if the output doesn't give you what you expected. You know that either the input or something in the function is wrong, and is much easier to troubleshoot.
The project im current working on have 3 layouts, 15 events sheets with 1834 events/functions. Imagine having all those in one sheet, without organization and lots of functions this would have gone wrong a lot time ago :D
So I would strongly suggest you start to organize your projects, even if they might be small now, just so you find a good way to work with them. I promise you it will save you a lot of problems and frustrations later on. :)