The Sims 8 in 1 Problem

i have installed sims 8 in 1, but when i'm installing the setup ask me for disc2.dat (or something like that), i insert second disc and then he ask me for disc3.dat, i insert third dics. but then it ask me for disc1.dat and i don't have this file.... what should i do?

if you dont have disc1.dat (CD 1) how did you start the install process?
its asking you to insert cd one again so thats all you should have to do.