Hi! I've just downloaded KDE a few days ago and obviously really new to using KDE on windows. and i was wondering where to get KWin? Thanks so much!

I am sorry but you can't get kwin on Windows. This component can't be replaced, so there is not even the possibility to get kwin. What you can try (but is only of alpha quality) is Plasma. For that you can start plasma-desktop.exe from the bin folder, after you installed the kde-workspace package.
Hope this helps.

If you just launch plasam-desktop.exe from the bin folder it doesn't replace explorer but runs on top of it. Is there a fix for this?