If you are used to editing programs you might be irritated that the default live playback of After Effects does not
play audio. To hear the audio you need to do a RAM preview.
For a RAM preview, you need to click the rightmost symbol in the Preview
panel. Alternatively, hit the 0 key on your number pad.
A composition is the timeline you want to work with - like a sequence in Premiere. When you start, each project has probably just one composition and it feels like the project is the composition. But when your projects get more complex, you start having several compositions for different parts of your project. You can even use some compositions as layers in other compositions to structure your project.
To add a bit more depth to your projects, you often want your text to be 3D. In After Effects, you have different options to achieve this and each of them has some advantages. So what option is best for you really depends on your project. Here are the pro's and con's for each of the options.
After Effects is very powerful when it comes to make animations that automatically react to the music or the sounds of your project. Here I give an overview over the most common workflows.
BeatEdit
BeatEdit is an extension for After Effects (and also Premiere Pro) which can auto-detect beats in a music track, wiggle to the beat, write markers, repeat keyframes, stagger layers, and more!