Try and set the "ScrollTo" behavior on your character. That means that the screen will follow the character and scroll if needed.
Remember that the window size must be bigger than the layout size, otherwise there is no room to scroll and the character will leave the layout.
Thank you for your reply, CodeMasterMike. I am going to try it! (Now rebooting to Microsoft Windows :))
Also there is a layout property "unbounded scrolling" that allows scrolling outside the layout.
Thank you for your reply too, but I have already used the layout property "unbounded scrolling", but nothing happened :(((( Is this a bug in the Construct 2 release?