If I have a file that I want to reference or put up to ask a question on how would I do that? Bearing in mind that I'm a new user.
We don't host files, and I would strongly discourage any questions that require you to reference uploaded files elsewhere. You're better off distilling your question down to a minimal example.
For images, you can upload them but until you gain at least 10 reputation you won't be able to include them inline. Just click the image button (or press Ctrl+G):
...and follow the prompts until you get a bit of Markdown that looks like this...
![enter image description here]
Then remove the exclamation point so that you can post it (once you're no longer a new user, you can skip this step).