These workouts can be done during all training phases.
On or off road find a course that has some grades around 4-8% that take 5-20 mins to climb. Stay seated and use a cadence around 60-70 rpm. Heart rate is not important, but cadence is. Pressure should be hard, but cadence slow,
Ride up hills that are 8% or greater. Duration of climbs should only be 1-2 minutes for each hill. Stay seated while climbing, using a gear a higher gear than you would usually use. Cadence around 50 rpm. Spin easily after each climb. Total climb should be around 30-45 min. Heart rate is not important.