Since you describe the "docs" as "not easy", I am concerned that you are only looking at docs.perl6.org and not also looking at the tutorial level information at perl6.org/resources. Have you looked at tutorials or introductory books?

A review of the tutorials led me to refine:

for @arr {
      say ( .map: {.fmt: "%7.1f\t"} ).join
}
[download]

for @arr {
    say ($_>>.fmt: "%7.1f\t" ).join
}
[download]