Warm up
:40 easy -> :20 moderate > :10 fast, rest 20 sec bwn
first with legs only, then only hands and last set with legs&arms. total time 4,5 min.

some short mobility as you like and start workout

Air Bike Conditioning
3 x 3 min easy , 1 min mod
rest 4 min
3x45s fast, 45s easy
rest 4 min
3x2 min mod, 1 min easy
rest 4 min
3x15s sprint at max effort, 45s easy

My rpm's with assault bike
Easy 58-60 (hold for 40min+)
Moderate 63-65 (hold for 20min +)
Fast 68-73 (hold for 5-15min)
Sprint 90+ (hold for 30-60 seconds)
Echo bike would be +4 rpm on each catecory.

Score those calories by each "work period"
example : 3x3 min easy + 1 min mod = total calories 150.
3x45s fast, 45s easy = total calories 60. etc..