I'm really new to After Effects and had a few questions
1- what is the best way to use the grain removing effect
2- If you're editing a whole home movie, 2 hours, and you want to apply an effect, how much of the footage does the effect apply to?
3- How do I cut out 10 sec. in the middle of the footage that has audio with video?
4- how do i play the footage in the program to know how it looks with the applied effects in motion?
1. I haven't used it a lot, but I think if you just play around you'll at least start to see what works. Don't expect miracles though. Also, it's SLOWWWW so keep that in mind.
2. I don't recommend you edit a whole movie in AE! It's possible, but not a good idea... best to use a proper editor like Final Cut Pro (on Mac) or Premiere Pro (mac and pc, by Adobe too). However, to answer your question : In AE, when you apply an effect to an item on the timeline, it affects that whole item. So if you had your WHOLE movie on one layer, any effect would apply to the whole movie. You can split the movie over multiple layers to control which bits are affected.
3. Don't know what you mean here. If you want to remove a section from the movie, you can split the layer at the points you want and delete the middle bit.
4. It sounds like you need to have a look at the manual :) It's very well put together, and has answers to many of the questions you will come up (such as HOW to do your question #3 and how effects work, etc).