Struggling to edit a video in after effects.

Hello there. I am a first time user of After Effects. Until now I only used the windows video editor that came with my XP but as it seems, that software won’t let me keep my aspect ratios of my movies if I want them at a certain quality, After Effect can. The problem is, I have no idea how to use the software. To start with, I would like to edit an existing video I have by cutting out certain small parts here and there. That would be easy in Windows video editor but I have no idea how to do it in After effects and the manual isn’t much help. Could someone here please tell me how to do it.

I should note, I am using After effects version 4.

Thank you.

via Video Editing Forums: Digital Director – Adobe Premiere, Premiere Elements, and After Effects