TMC Smithlands

I am starting a new job @ houston methodist in the medical center. I am very confused on parking. We are supposed to park at smithlands and ride the metro rail to the hospital, I have never been on the metro before and have no clue how it works lol. Is there a specific train that will us to methodist, where do you go to get back on to head back to smithlands? I tried to ask my HR rep but she really was no help and told me my best bet was to ask those around me.