After reading 
Fronne 's tutorial on mulitple screen sizes, I think that I understand that the ratio of my game's display is what is important. I want to make a side scrolling game that looks like a city block (several unique buildings on the block that my player will interact with). My layout will be very wide so that my player can walk from end to end of the street. However, I can set my window to the 16:9 ratio, right? As long as the math of the window follows this ratio I am good for displaying on different devices? I am TOTALLY new to this (an artist, not a programmer...trying to become a one stop shop for gaming content) so I am trying to wrap my head around this. Please, help!
BTW, the tutorial is found under the beginners section with the title "Multiple screen sizing for all mobile devices". I am too new to post a link.