I read wiki and some discussion but I don't understand the difference between rating and ranking.

Who can give an explanation for newbies?

Rank is what position you currently hold. Rating is your skill level. Higher rating gives higher rank.

Dan is correct. For example, if you have the third highest ELO on the ladder (your ELO is your rating) your rank would be 3.

the player with most points (rating) is ranked first (ranking)

the second player with most points (let's say it's 2252) is ranked second (rank 2).