(Note: the C1 levels were for the pre-alpha version of the game from 2014 and do not work with Carma: Max Damage, and unfortunately they haven't been updated yet either.)
If you're looking to install some other mods for C:MD, here's some links:
Mod installer: http://www.carmageddon.com/forum/topic/28798
Modding forum: http://www.carmageddon.com/forums/modding/carmageddon-max-damage
(I'll also leave a link to the C1 level pack as soon as it gets updated for C:MD)
