To open these views manually, select Window->Show View->Other...->ACTF and expand the ACTF node and open the desired view.
To reset the perspective, select Window->Reset Perspective.
The best place to start is by looking at the Tasks section of this document and working through some of them. In that section, you'll find step-by-step instructions for doing some of the things for which the ACTF validation components are commonly used. These will provide you with an introduction to it's capabilities and then you can use what works best for you.