hi i need help with this script idk how to trigger it when the meteors hit land how do i do it? [closed]

howhi = 100 
howfst = 4
while true do
    local nmbr = 0
    while nmbr < howhi do
        script.Parent.CFrame=CFrame.new(script.Parent.Position + Vector3.new(0, howfst/4 , 0)) * CFrame.fromAxisAngle(Vector3.new(0,1,0), 0)
        wait(0.25)
        nmbr = nmbr + (howfst/4)
    end
    script.Parent.CFrame=CFrame.new(script.Parent.Position + Vector3.new(0, -(howhi), 0)) * CFrame.fromAxisAngle(Vector3.new(0,1,0), 0)
    wait(0.25)
    nmbr = 0
end