Looking at the notations on the video it seems very similar to what’s in the guide. Here’s the combos from the guide and the notes under the damage and meter gain. I’m sure there’s more ways to expand on all these combos with assists to squeeze more damage in.
The guide has 3 follow-up combos depending on the distance to the corner from :f::h:.
(Opponent closer than halfway to corner)
cr.:l:, , st.:h:, :f::h: xx :rdp:, j.:h:, LAND, j., j.:h:, j.:s:, LAND, cr.,:h:, :s:, sj., sj., sj.:h:, sj.:s:, :dp::l: xx :qcf::atk::atk:
738,100 damage, 6% meter gained.
After the Mass Change M, hit your competitor with air :h: as late as possible to give yourself enough time for the subsequent normal jump and air .
(Opponent cornered)
cr.:l:, , st.:h:, :f::h: xx :qcb::s:, j., j.:h:, j.:s:, LAND, j., j.:h:, j.:s:, LAND, cr.,:h:,:s:, sj., sj., sj.:h:, sj.:s:, :dp::l: xx :qcf::atk::atk:
755,400 damage, 19% meter gained.
Distance requirement to the corner is fairly generous - even if your attacker is a fair distance away from corner you can still perform the combo by flying forward after the flight cancel.
(Opponent farther than halfway to corner)
cr.:l:, , st.:h:, :f::h: xx :rdp::l:, AIRDASH DOWN j.:h:, LAND, cr.,:h:, :s:, sj., sj., sj.:h:, sj.:s:, :dp::l: xx :qcf::atk::atk:
700,500 damage, 13% meter loss.
This combo requires you to cancel Dark Matter into Mass Change L with an unintuitive timing - immediately before the opposing character is about to hit the wall. After Mass Change L air dash down immediately and press :h: before they hit the ground.
This next combo was one of the more interesting combos from the advance section.
(Opponent cornered requires 2 destruction, 1 creation)
cr.:l:, , st.:h:, :f::h: xx :qcb::s:, j., j.:h:, j.:s:, LAND, j., j.:h:, j.:s:, LAND, cr.:h:, :s:, j. :qcb::h:, :s:, sj., sj., sj.:h:, sj.:s:, :dp::l: xx :qcf::atk::atk:
940,900 damage, 91% meter gain.