A 2D scroller is a very simple concept, even if it doesn't appear it at first usage. Use sprites for your character and platforms/objects; to insert these double click the layout area, and find Sprite. After you've inserted a character, you can give it movement by clicking it, expanding 'Behaviors' - in the properties bar on the left - and adding a Platform behavior. To give it things to walk on, after inserting some platforms, click them and expand the 'Attribute' category. Check 'solid' here, and then when you run your game (Run under the 'Project' tab) you can move about on the platforms.
To add scrolling, you can adjust the layout size by clicking a blank area of the layout, and changing the width/height. Then click back on the character, and check the 'center on me' attribute. You'll then notice that when walking about, the screen follows the character.
If you have further questions, don't hesitate to ask.