How to use static libraries in Objective-C (OS X)?

I am a novice programmer using Xcode, and I am trying to create a static library so that I do not have to copy files every time I write a new program. The problem is that I could not find a satisfactory explanation of how to do this - I tried several tutorials, and I'm sure I skipped some steps. So:

I have an Xcode project with my class files. He got a class for handling large numbers called Large - Large.hand Large.m. I decided to make it a static library, and I created it.

Then I made a new project and followed this . I tried #import "Large.h", but Xcode still did not recognize the class Large, as in my projects, which have a copy of the source files themselves. I probably do a lot of things wrong ... What should I do? Many thanks!