Help trying to uninstall mavericks

Is it possible anyone can help me, I'm trying to uninstall mavericks back to osx 10.7 does anyone know how or what I need to do. Or even if it is possible. Thanks.

I have tired many of different ways but none seems to be working the worse problem I have can across is when I try to install 10.7 it says that's the software is too new.