The beat the song is built on is one bar, played through bars 3-6, 15-18 and 31-34, and 2 more places -- 30.9% of every bar the kit plays. That is the spine of it; everything else is what happens around it.
It is played on snare, floor tom and kick, counted in sixteenth notes. On its own it scores 27 out of 100 -- a fair first song -- and the thing that decides that is how much of it falls off the beat.
The whole song is 71 out of 100, so the beat is not the hard part: what costs you is everything around it, the joins and the fills.
A part this hard is not learned by playing it slowly and hoping. The room opens it on its simplest reduction -- the timekeeper alone, at 63 BPM -- and adds the notes back over 3 rungs, each with a tempo to reach and a gate to pass before the next.
Tempo goes 63, 74 and 84 BPM, and the gate at each one is 8 loops in a row with no wrong note and no wobble in the time.
PRACTISE THIS BEAT →A one-bar groove on snare, floor tom and kick, in 4/4 at 84 BPM, counted in sixteenth notes. It is written out above, and it covers 30.9% of the bars the kit plays.
Bars 3-6, 15-18, 31-34 and 48-51, and 1 more place. The time is kept on the toms to start with, and it changes 8 times over the song.
27 out of 100 on its own -- a fair first song. The song as a whole is 71 out of 100: demanding, mostly on the independence between the hands and the feet.