And in post 16, the analysis is faulty.
1.Rd2+ does work, but not with the follow-up giving in the analysis. After 1...Kc7, then 2.Rd4!. Only then do you start walking out with the King!
The steps are simple:
1) Get the opposing King 3 files away from the pawn (minimum - more is fine)
2) Build the Bridge by putting the Rook on the 4th rank (5th rank if you are Black).
3) Wiggle the King out until the check by the opposing rook can be interposed by the pawn.
4) Don't ever move the King two files away from the file the pawn is on. If the pawn is say, an e-pawn, the White King should never be on any files except d-, e-, and f-.
It's not faulty. It's done on purpose to show that the king alone can't win that position.
The other thing to keep in mind is that it's not about how many times it happens. It's about knowing patterns and how many times it CAN happen. I might make one move over another in a R+4P vs R+3P ending, where I'm down the pawn, because going with Option A leads to a drawn position, but Option B gives my opponent Lucena's position.
So Lucena's position doesn't have to happen for it to be important. Just knowing it helps you prevent it happening when you are down a pawn, or may drive you to what you need to do to simply your R+4P vs R+3P down to a winning R+P vs R position!