I think most of us started with an idea "How do I do this quicker, more accurately or more consistently" and start from there, building up knowledge as you create LISPs to do what you want to do.
I use a lot of online resources, this forum is great by the way. For learning don't ask for a complete LISP since you are likely just to save that and not learn how it does what it does, but ask for small portions of code. Use these codes in your projects
Apart from here, there is another forum, TheSwamp which is also good.
Online:
AfraLisp has a lot of good examples,
Lee Mac has a lot of small functions which can be used to build larger functions or as stand alone functions
AutoDesk has online help for all the functions
As for creating a LISP, it is a text based language and you can use any simple text editor to write the code as the simplest form
First off though I'd look on Lee Macs website for his tutorials on writing and running LISPs