You have to change the starting location of the character via the characters properties tab.
You can however use the console while game is running through the editor to quickly change to another scene.
press TAB to open up the developers console. Next type change scene then press space & it will show a list of your scenes. Use the arrow keys to select one & press enter or type it in or begin to type it in & then press enter. You will change to the scene you specified & it will automatically place your character somewhere inside of the scenes way borders that you should have create for the scene.
Quick note: the console features an autocomplete system, so once it highlights something that you were beginning to type you can press enter to have it autofill the rest of the word. Pressing space after will open up the next autocomplete list of commands or whatever it is that are allowed to enter.
type help for a full list of available commands.