I'm using Flare to develop a visualization. Being familiar to Java, Javascript and Eclipse it wasn't a big deal to familiarize myself to developing with Actionscript and Adobe FlashBuilder. I actually found that the learning curve is very flat. However, being new to Actionscript, I can't figure out how to use the Spark libraries that are part of Flex. I tried to add the libraries to the build path, with no success. I guess I'm confused about how Flash, Flex, Actionscript, Spark and Flare work together, even after reading the helpful answers on this question Does anybody know which part of the puzzle I'm missing? Thanks.