So there are the fps numbers in top left in green right? Once you start recording they become red. And when you stop, they become back to green. Easiest way to record and stop recording is pressing F12 from what I believe. AFter you finish uploading the video, click this (In the red box) Here, it will appear all the videos you made. You can play them of course. Then, you go to your youtube channel, click upload and this will appear Now open what I told you earlier, the place where are videos. Then do this. Drag the video from the file into the "Select files" aka the arrow box. Now you can rename the video, and edit it (idk how). It will take more than you will expect it will.
I believe you are asking how would you upload the video to the forums? If that's what you mean you would have to first upload it to YouTube. Then when it's done, copy the URL of the video. Once you have that copied go back to the forums and click the 2 film looking strips in the tool bar. Paste the URL into the media box (there should be a place where you can paste the URL of the video). Then the video should show up.