Use a metronome. Set it to MM=120.
"Play" the whole exercise with fingers only. Stike valves hard and rhytmic on the metronome clicks (not after). Keep the pinky finger away from the fingercrook.
2. Finger + breathing.
Repeat the exercise, but this time "breath" the notes: TOO - TO - TO (big OO feeling)
3. Finger + buzzing (legato)
Repeat the exercise, but this time buzz the notes (2 bars in each phrase). If you cannot buzz up to D, transpose the exercise down a bit. Use a BERP and finger the notes. If you have no BERP, tape the mouthpiece to the leadpipe.
4. Finger + buzzing (attack)
Rest as long as you palyed or more. Do it again but this time strike vervy note with the tongue.