Hi,
I don't know about "emailing" to the forum, and it may depend on the "User Interface" or "App" that you're using (Windows PC, Apple, Android phone, etc.) but you should have an "Attach Files" (paperclip) button below the window you've been typing in.
Alternatively, you can often "Edit > Copy" files, or put things into the "Clipboard", and then "Paste" (Edit or Right-Click) them directly into the Forum Editing window. And have you tried "hovering" over the icons at the top of the Editing Window to see what they can do? Note the forum also has a "Sandbox" if you want to try things out without directly posting to us.
Cheers, Alan.