You hear the deacon at the beginning of the first clip. The bells are on the chain of the censer.
Matins. God is the Lord. Kievan chant. Five (all men) at the kliros.
Matins Evlogitaria of the Resurrection. Znamenny chant. Three (men) at the kliros.
Matins. The Magnificat, always the first thing that gets congregational participation, so it’s impossible to say how many are at the kliros.