When I attempt to SpaceSpaceEnter to move to another line, It actually is creating a new card? Can someone help me with what I am doing wrong?
While it's not possible to put in line breaks, since the columns / cards are fixed width, you can easily work around this limitation by just adding some white space until you fill in the line and the text naturally jumps to the next line.
Normal spaces will get ignored though, so go for something like ideographic space (just grab it from inside these square brackets): ] [ or go hunting on Wikipedia.
Trello card titles do not respect Markdown (so having two spaces before pressing enter will not create a line break), but they will overflow to two or more lines if they are too long for a single line. (As mentioned above, the description and comments on the "back" of the card support line feeds.)
When resizing the board, you can expect this line wrapping in the card title to change as well. It would be nice to have a way to force a line feed in the middle of a card title, but I can't find one at this point.