You can ask somebody how to spell "please"- that's easy. As for debugging a plugin, it's a harder process, especially if the plugin is a larger one. If you know how it's supposed to run and function, then run it in your server and attempt to utilize all of the features. It they don't work correctly (or not at all) or if one of them crashes the server, then that's a problem. In terms of fixing them, you'd first have to know how to program in PHP (of course). If you're lucky enough that an error comes up when something fails or breaks then you can look at it to find the problem. Fix said issue, try again and repeat the process. As you can probably imagine, this is easier if you're the original author of the plugin.