You have the 'RTFM' badge, but you obviously cannot have read the manual prroperly.
What you are asking is essentially the difference between the Project Windows size and the Layout size.
Your second question is even easier if you have looked at any tutorial. There is a System Action called 'Go to Layout' which you can utilize by have a condition that tests for a particular thing happening, such as a collision with an 'end of level' object, for instance.
My sincere advise - try at least 1 or 2 of the most popular tutorials. You will find they are a valuable learning resource.