To record a video of Principia, just follow these simple steps.
Download a Video Recording Software
We'll use a free and open source software called Open Broadcaster Software. This software is mainly used for live broadcasting but can be used for video recording as well.
You can download it here: https://obsproject.com/download
Recording a Video of Principia
Open up a level in Principia that you want to record.
Click the Settings button in Open Broadcaster Software.
Once in the settings window, select Broadcast Settings from the list on the left.
On the right at the very top change the option Mode from Live Stream to File Output Only. (see screeshot below)
Set the File Path to where the recorded video will be saved. Open Broadcaster Software does not overwrite files, it adds (#) to the end of each duplicate file, where # is a number counting up from 1.
Under Sources, right click and select Add -> Game Capture and give it a name (e.g Principia).
Now select Principia under Application
Now just click Start Recording and the video will be saved to the file path you chose.
If you want to edit your video you can use Windows Movie Maker. If you don't have it you can download it here.
Sharing your Video on the Website
If you have any questions you can post them on the forum.