To switch between windows, OS X uses Mission Control > http://support.apple.com/kb/HT4689
1. Go to System Preferences > Mission Control and disable Group windows by application.
2. With the app running and one of its windows selected, open Mission Control and switch between them
I'm sorry I didn't explain my problem very well. I sometimes want to view 2 or 3 app windows on the same screen(workspace) so I can see them simultaneuosly. I can do this by manually moving and resizing the windows which takes too much time. In Microsoft Windows I can perform this function by selecting either: tile windows horizonally or vertically on the workspace so that all the space is taken up and no window is covered up. So far I have not found a similar function available in OSX. Keep in mind, I want to see the separate app windows on the same screen.
I remember being able to tile windows in older versions of OSX, but I could be completely wrong. Right now I'm using Divvy and I quite like it. http://mizage.com/divvy/
Its 14 dollars but there's a trial version. Its not the same as telling all windows to tile but its the best solution I've found.
There are other apps out there that are similar but I've only used this one.
I have been using an app called BetterSnap Tool for a few years now. Easy to use and all you have to do is drag windows to where you want then to be... Works like the snapping tool in Windows, but better.
Works with a two monitor setup... I have a three monitor setup and it works great.