Boundaries in contact between a man and a woman?

[Euphorium]

Peace be upon you,
I live in Germany and I'm a student in university. I was born Muslim, but lately I've been trying to put more effort in and research on how I can become a better Muslim (because I felt like I was lacking)
While studying it's almost impossible to have no contact with students of the opposite sex. Because specifically not talking to female students would make me come off as unfriendly or extremist and give people a bad idea about Islam.

So my question is how much contact is allowed between a man and a woman in Islam? (assuming the woman is probably not even muslim)
I hear often that contact is actually allowed, but with respect and under Islamic rules, but what are those rules? I want to know because I might be breaking them (i have a big friend group half of which consists of females, so I'd like to know if I should slowly cut ties with this group)

I would be very grateful if someone gave a detailed answer to different possible situations, like texting, talking/ meeting in person (in a group or alone) etc.

[- Qatada -]

Asalamu alaykum.

Just be formal. if you have to talk for work, then you've got no choice so just do it. But you don't need to have unnecessary conversations. Also try to avoid being alone with any of them, because shaytan is the 3rd person there. Your friend circle should really just be boys.