Questions & Answers about Утром мы дошли до пирса, и оттуда был виден старый маяк.
Утром is the instrumental case of утро and is commonly used as an adverbial expression meaning in the morning.
This is a very common Russian pattern:
- утром = in the morning
- днём = in the daytime / during the day
- вечером = in the evening
- ночью = at night
So Утром мы дошли... means In the morning, we reached...
You do sometimes see в + time word, for example в то утро = that morning, but for the general meaning in the morning, Russian usually just uses утром.