What Rituals do Catholic perform/what do they do in the mass that demonstrates a belief in life after death?
Excluding prayers they say.
First off, the entire mass IS a prayer, so that’s a little bit of a problem if you are excluding it 😛
However, baptism is rebirth into eternal life. The sacrament of the Eucharist is likewise an affirmation that Christ died and rose again to restore us to eternal life. The mass itself is modeled off of the book of revelations (in addition to being modeled on Jewish Synagogue and passover), and the book of revelations details the eternal worship of the saints and martyrs in heaven.
Ultimately, the entire mass speaks to salvation and resurrection to eternal life