This theme is only for other distros, not Linux mint and for those it depends if they ship both versions of the theme (over wise you can install it manually)
If your distro ships it, just go to Settings > Themes > Style and select the one you want. If your distro doesn’t ship it go on Advanced Settings > Add/Remove and then you should be able to find it there (you can also manually get the theme and decompress it to ~/.themes if it isn’t available in the theme repository)
an i switch back to the old layout n stuff?
Im really not jiving with this new look
This theme is only for other distros, not Linux mint and for those it depends if they ship both versions of the theme (over wise you can install it manually)
so how do i change it back without downgrading
If your distro ships it, just go to Settings > Themes > Style and select the one you want. If your distro doesn’t ship it go on Advanced Settings > Add/Remove and then you should be able to find it there (you can also manually get the theme and decompress it to ~/.themes if it isn’t available in the theme repository)
Changing themese does not change the dialogue menus and popups
At least with Linux Mint, you can still choose any of their older themes (Mint-X, Minty, Mint-L), so I expect them to still include those.