Questions & Answers about Я обычно встаю рано утром.
Russian often talks about time of day without a preposition, using the instrumental case:
- утро → утром = in the morning
- день → днём = in/at the daytime
- вечер → вечером = in the evening
- ночь → ночью = at night
So рано утром literally is “early (in) morning-INSTR”, but in English we translate it as “early in the morning.” You simply learn утром as “in the morning” in this kind of sentence, with no extra word for “in.”
Обычно means “usually / normally / as a rule.”
- Я встаю рано утром. – I get up early in the morning.
- Я обычно встаю рано утром. – I usually get up early in the morning (but not absolutely always).
So it adds the idea of habit / frequency.
It’s not grammatically necessary, but it changes the meaning from a simple statement of fact to a statement about your typical routine.