I´m trying to animate already existing 3D scans of plants (like megascans).

From minute 9:00 simon fiedler is explaning his approach:
https://www.youtube.com/watch?v=ysujwGvr2_8 [www.youtube.com]

I don´t understand how to use the delte sop in this example, as i´m always delting almost all points.
do i have first to overlay all geometry in the same uv space?