A DLL is a library that contains data and functions. These functions are packed in such way that you can use them when you know the function name and its arguments. There are a lot of tools that shows you the function name but if you don't know their arguments the dll is of no use.

In Windows, Microsoft has provided this information in a guide: The Win32 Developer's References. Without this guide you are lost or you must have found a code snipped in another programming language that helps you further.

You can also buy thirth party dll's for other specific use. These libraries have always documentation how to use the functions and for what purpose.

There are dll's you may not use directly by calling their functions, even if it's part of legal purchased software. So read your software licence careful when you install the software.

Alpha Five provides you with Xbasic commands to access these DLLs and the functions in it. With declare and declarestruct you'll get a lot of functions running.