seamless animation?

An animation is just a series of frames (still images) one after another, really fast, so your brain thinks you are seeing moving objects. Filter Forge renders still images, so if you want an animation, you have to render a "batch" of images and maybe make an animated .gif out of them. The "slider" for animation can be any slider in any filter!

Filter Forge comes with a "batch" program, but there is no graphical interface. So, some cool users decided to make their own!
Batch GUI Tool for Windows
Batch Render for Mac

Here's a wikipage on animation.
http://filterforge.com/wiki/index.php/Animation

Most of the teaching comes from users themselves. FilterForge, and many other nodebased / programming tools alike follow a very DIY philosophy. It's very customizable and it has a lot of freedom which is why a lot of "teaching" is case-by-case. The program shares a variety of levels from what's simple and clean, all the way to extremely complicated. But everything has some kind of stepping stone and you can't swallow this program in one go. The roots grow very deep, so exploring it would be a step by step process.

I assure you though, that me and many others here would be able to help you. So if you got questions, don't shy away from asking. When you start getting it, it really becomes one addicting program.