For cardio : workout at your target heart rate. For HIIT: varying intensity from high to low or rest ( no slow pace) For strength: you should lift enough weight to complete the needed number of reps and sets.
Time:
For cardio 30- 60 min For HIIT 45 min (short periods of bursts followed by rest)
For strength depends on the amount of weight.
Type:
Either cardio, HIIT or strength training (resistance training)
NOTE: This info is given by an unqualified brofessor, who uses his hard gained bro-science in the expense of scientific facts to solve others broblems.