How can I play a 7-string guitar song on a 6-string?

I'm trying to learn Solitaire Unraveling by Mushroomhead, but I see it's written with 7 strings. The tuning is (ADGCFAD) Not quite sure what tuning that is, I've only been playing for about a month. Am I able to still play it with my 6-string Ibanez?

tune the guitar is drop c which would CGCFAD. basically tune the 4th string to the same sound as the 6th.