After one’s death, where do they go? To a different world, or do they attain Moksha? What is the connection between Shraddha, Tarpanam, and death? How to understand?

This is a general rule; if one does good deeds, they will go to heaven, if one does sins, they will go to hell, and those who surrender go to Moksha. We perform shraddha to pitrus, and it reaches them.
We could not decipher on what basis you have asked the second question; it is better to learn such scriptural matters through your Acarya.