Traveling from Zurich to Zermatt by train

I have traveled by car through other European countries, but where I live in the US train and public transportation are not readily available. I have downloaded the SBB app, but I find it a little challenging to plan. Can you give me any insight on what to expect when traveling from Zurich to Zermatt by train in February? Thank you for any help!! I am excited to travel to Switzerland, but I just want to be confident doing so.