First, once you're out of bed at an appropriate time, you want to stay out of bed.
Second, the minimum interval of sleep you need to actually rest is 15 minutes. Snooze alarms, even on mobile devices, are currently 9 minutes.
Third, tangentially related, do not use an obnoxious-sounding alarm, because you will make a negative association with your necessary tool. Use pleasant or inspiring music.
Source: I am a person with chronic depression who managed to solve this issue for myself.
For me, even not depressed, "[d]o not use the snooze function" means "turn the alarm off and sleep in another three hours."
Obviously if it works for you it works for you, but if you don't have the willpower to stay out of bed, as I generally don't, at least the snooze button gives you another chance to wake up at a reasonable time, which puts the day on the right track.
First, once you're out of bed at an appropriate time, you want to stay out of bed. Second, the minimum interval of sleep you need to actually rest is 15 minutes. Snooze alarms, even on mobile devices, are currently 9 minutes. Third, tangentially related, do not use an obnoxious-sounding alarm, because you will make a negative association with your necessary tool. Use pleasant or inspiring music.
Source: I am a person with chronic depression who managed to solve this issue for myself.