Best way to network with older colleagues?

I just started an internship at a buy side shop. Generally the days are quiet and not much talking going on, people eat lunch by themselves and things like asking clarifying questions or getting up to get water feel like a disturbance. I figure besides performance, engaging with the more senior people at the firm is a good strategy to getting the ft offer.

What’s the best way to reach out to the older, more established people given that it’s difficult to put myself out there in a rather quiet office? We have an internal platform, teams, etc