I was trying to understand what object decomposition means and read a lot of stuff on internet but every resource talks in terms of lots of keywords that i couldn\'t understand.
I think you've basically got it correct -- mapping the "real world" things you'll be working with to representations as objects in your code.
Sometimes people call this modeling, because they are creating a "model," in code, for things and concepts in the real world, like employees, accounts, birthdays, cameras, etc. -- some physical, others ephemeral, but all needing to be represented as objects in code.