Yeah that video is quite difficult to follow and he seems to be saying if you have a Van Nistelrooy you play the common one up front with two winger/inside forwards on the flanks but with a different type of forward you play him behind kind of 'in the hole' and then that begs the question what do you do with the other two forwards, are they still winger/inside forwards so you have no striker, or do you have them more central?
A good book to read if you are in to this type of stuff is Jonathan Wilson's Inverting the Pyramid. He discusses the development of all sorts of different tactics through history. On Ajax tactics, he says basically it often traditionally lined up as a 4-3-3 with one of the centre backs effectively stepping up to be a holding midfielder, so becoming a 3-4-3 with a back three that marked zonally, a midfield diamond and two wingers flanking a striker. In the section on Van Gaal it says by the 1990s (Van Gaal's time), defences had learned to clamp down on the attacking midfield style playmaker so you needed a playmaker to be that centre-back turned midfielder (he used Wim Jonk). The guy at the head of the diamond was then a hardworker/hassler midfielder who chose the right moment to join the attack as a second striker, whilst the main striker was more there to play one twos and create space for other players. The difference between the Van Gaal approach and the traditional Ajax from the 1970s was that in the earlier "Total Football" days, midfielders would run beyond wingers to create overlaps.....LVG didn't want that.
The traditional style Ajax total football was defined by the pressing game and the centre-back-cum-holding-midfielder, that was the key innovation, and the fact that they played a very high defensive line so it compressed the pitch for the opposition.