Yeah, so did I.
Objective-C is a programming language developed by Apple for use in programming for the MacOS and iOS platforms. As you may have guessed, it's based on C.
You might find it helpful to take a few minutes to learn a bit about the C programming language. You can use XCode as a C complier and try out some test programs in C.
The classic text on C is the book written by the folks who created the language and it's called, strikingly enough, The C Programming Language. You can get it on Amazon.com if you like.
This website also gives a simple introduction to the C language and it's worth reading through.
One other thing folks often find difficult about Objective-C is the fact that it's an object-oriented programming (OOP) language. If you're new to programming and object-oriented language can be difficult to learn. Many volumes have been written about OOP, but what it boils down to is this: a class is like a jello mold. You can fill the mold with different colors and flavors of jello, but what you get each time you turn out the mold is the same shape with the same properties (it wobbles and is tasty). With that in mind, you can think of a class as a blueprint from which copies of similar objects can be created. For more on OOP, check out this website.