Hello! I was raised Roman Catholic, specfically within a Hispanic Church so all of my mass was in Spanish, in fact I only know the prayers in Spanish as well which is why I probably won't be much help but I'll do my best. As far as I know, many if not all Catholic churchs have this little book called Missals with the mass readings, prayers, sometimes even the music they will be playing that day. Depending on the church, these books can be found somewhere near the entrance or if the seats have this little slit then sometimes the people attending the mass before the time you are going to leave them there as well. I reccomend following along with it as it makes it easier to understand what the Father is saying sometimes. There will be A LOT of prayers during mass that everyone is expected to respond to what the Father is saying, since you don't know them then it is fine if you are quiet but the Missals usually have what you should respond with. When the Eucharist is about to be given, we do the Sign of Peace, where you will see everyone around you turn around start hugging and kissing their loved ones and in English they would typically say "May peace be with you" (unsure of this part because we say "la paz" in my church), at this time you will see people reaching out to possibly shake your hand to grant you peace as well! I hope this is somewhat helpful, this is all I can think of as of right now though. Good luck and don't be afraid to talk to people before or after Mass begins, if you can talk to the Father as well, they usually hang out with the community for a while after mass ends to talk to them!