Hello there! I'm unsure of how to use the replay viewer. I downloaded the batch file and it just says "change the variables at the top". I don't know what that means because I'm not very computer literate.

Hello! I'm not sure what you mean by replay viewer, where did you download it from and what are you trying to do? If you wish to view your replays you go into time attack and play back your fastest replay, if it's someone else's replay then put that replay into your SRB2Kart folder and use the command "playdemo <filenamehere>.lmp" without the parenthesis present in the console menu by using the tilde key on the main menu