The putting green(s) already exist. Use the 10 shots WGT gives you to putt around on any and all greens, from all courses. This is why a putting green or driving range isn't necessary.
Putting is a very difficult part of the game and takes a lot of skill to master. Everyone goes through days when nothing drops, we just have to take the good with the bad.
Like Leon said, the "search box" will yield a million and one threads about the putting green issue.
Happy putting!