Don't know what is the problem, but when I try to do this process at 5:04. In my Blender cloth filter with "filter type" - inflate works only on axis Z, inflating strictly up and down. Can't inflate object like balloon. Maybe you know where is option to indicate inflating direction? Apply force direction on axis (buttons X, Y, Z) doesn't work at all for me. I use blender 3.1.0 beta and tried to do it in 3.0.0. Update: I installed Blender version 3.1.0 and Apply the force in the selected axis X,Y,Z started working. Sorry for bothering you.