Well then accept an official welcome to the guild. I for one look forward to seeing what you have been working on.
Posting is pretty simple, you will want to use the "attach" (paper clip icon) when it comes to posting your images. That will post them with a thumbnail that can be clicked on to enlarge. Also, images can be up around 4MB in size so you hopefully won't have to reduce it too much. Whatever filetype you have it saved as you will want to create a .jpg version for posting. That may require an 'export' or 'save as..' from within your software, I think you said CC which I don't know anything about. You can always use the 'Go Advanced' button in the bottom right corner to double check what your post will look like before you post it.
That's just a really quick run down of posting here so don't be afraid to ask questions if anything is unclear. I'm waiting for someone to pull up in front of my house right now so I can't get too detailed