I think for the people with the Lian-Li screen it's a little confusing at first both due to Lian Li's lack of documentation and how the screen (which is essentially a turing) was implemented into the software.
I love a lot of lian li's products but their support has always been lagging.
There are articles out there saying rename to the extension to .theme some that say .template. We now know it is .template but then they changed the software again so that after renaming it to .template you have to zip it also. FOLKS .zip not .7 zip.
Some themes will install your mp4 from the .zip some won't. FOLKS for the ones that don't add it. Add the .jpg or .mp4 using the change background function after applying the template.
Lian Li also does not allow you to add any additional fonts nor add any other modulars to my knowledge. You can replace one of the original fonts or so I've been told by renaming the desired font to one of Lian Li's fonts but you might want to back up the original fonts.
Also I have yet to find a way to export actual themes from Lian Li and cannot figure out where it stores created or imported themes.