I am not sure about this tutorial at all. He tends to fiddle a lot and not explain why he sets things where he does.
Not enough info about attack settings. Get this wrong and you are screwed.
A great mix does not require a multiband compressor either. Many great mastering engineers here in Melbourne do NOT use multiband compression.
They are a bit dangerous because when individual bands compress the tone can change. You need to ensure in order to maintain correct tonal balance that all the bands have very similar gain reductions. I agree they can be useful when you are dealing with a bad mix or a mix that has some drama in a certain area of the mix. But if you do a great mix that won't be present.
A great mix will compress nicely with about 1.5:1 ratio, about 2 to 3 dB of gain reduction and attack settings at least 10 mS to allow the transients through. Release times can vary but generally longer eg 100 to 300 mS. Depends on the groove and tempo of the music. A good place to start re release settings is calculate how much time a crotchet takes up in the music and start there and work down from that point.
The constant zooinmg in and out is also stupid too. I wonder who the person was who organised that! Someone who does not know anything about video production obviously.