Does the Webhook CMS area have a file management area? i.e. for simply creating folders and uploading files such as images, PDF's etc? I can't seem to find where/how to do this.
You can't really do this remotely (i.e. by logging in to the CMS - there's no "general" images folder like you have in WordPress). But within the project folder, you can create folders and such. The sites do come pre-built with a couple of very important folders and once you understand what they are for, and how the CMS works then you'll be able to build the ability for what you're asking within the CMS content types itself.
What I typically do, is upload all the basic image assets to the static/images folder, that way I have them there in case I don't have a place in the CMS set up to use them. Then I know where all of them are, and I don't have to hunt through all the other files I may have created that aren't necessary to the website. And, if I choose, I can hard-code them in (I don't normally do this, but this makes the option available if needed).
I could go into too much detail and I started to do this, but unless you understand that you are building these types of things in the CMS, then nothing else I say will make sense.
Let me know if you'd like me to elaborate on anything else or at least tell you how I do this stuff.