You can not upload vids in MTF as you do with pics. You have to upload them somewhere else and pòst the links (as Alexito does with the tennis pro videos, for example)
Some sites to upload videos:
(this 2 are the ones that are more used, so I supose are the best...
(can´t really say nothing about the last 4..., I have the links of the sites, but never tried them)