TITLE: Pre-requisites and references for $K3$ surfaces
QUESTION [8 upvotes]: I would like to know the "roadmap" to study $K3$ surfaces. 
Perhaps, my background might be helpful: I am an undergraduate student, who knows the basics of Differential Geometry, Topology, Complex Analysis, Abstract Algebra. I do not know Sheaf Theory. 
My question is: What should I know first before trying to understand the basics of $K3$ surfaces? What are the minimum pre-requisites? Any references that might help me build up a foundation in me? 
Please suggest in comments, if you like this question to be improved for more clarity.

REPLY [3 votes]: Here is a great reference I found (in case someone might be interested): 

http://www-math.sp2mi.univ-poitiers.fr/~sarti/corso_Perego.pdf