Welcome to Zurich and to EF..I'm rather new here myself..just arrived in Zurich a month ago and will be here for a year.
I'm quite lucky to have found a couple of friends here but of course it is never the same as back home so I've had to venture out myself quite a bit.
One of the easiest things you could do alone, if the weather permits, is to take the S10 to Uetliberg, where you get a nice view of the whole city..then do an easy 1.5 hr walk to Felsenegg and take the cable down to Adliswil where you can take the S4 back to HB. Note that the Zone 10 card is not valid for Uetliberg so you would have to buy a 1-2 zone upgrade if you just have the zone 10 card. It is possible to do longer hikes as well and I've been hoping to do so..but the weather hasnt been great
To meet people, you could take German classes or join language exchange groups. I believe EF organises one in Zurich weekly. I have been to the one on meetup.com called Stammisch. They meet every Thursday evening at Fork and Bottle and all are welcome, though I think it helps if you have some prior knowledge of German.
Tomorrow's weather forecast is bad so I'll be hiding in the Landesmuseum. You're most welcome to join me there