I have a static menu that when I press the 'play' button, before the film starts playing, I want an effect I have created in After Effects to play (the AE file has the same menu, with an effect applied to it), and after that the film starts. I hope that makes sense! What is the best way to achieve this?
With the button selected that will play the movie, in the properties panel, you should see a 'Transition' tab. Set the transition to the asset of your transition animation. It can only link to a single asset, so if you want audio with it, you should create an After Effects composition that has the video and audio of your transition and import it into encore using dynamic link.