I'm having trouble getting GDI sample codes to work, I've seen the external packages and downloaded them but I couldn't get the same code to work and I believe it's because I don't know how to install the GDI packages properly, can anyone help me?

Ahh ok great, now I just need to know how I can install it :P. There is a bunch of files in there and I have no idea how to get them to work. Can anyone help me? Do I have to open up one of the files in Delphi? If so which file should I open, there are a lot of demos and tests in there :S.

Just add the pas folder to your project's search path.

You can look at the demos for how the function from the API work.

Here's a FAQ on GDI+ (examples in C), but the explanations may help you.