Thanks for making an effort, @taka-aoki!
Because most people import raw data (not alpha diversity results), there is no specifically tailored example in our documentation. One way to get raw alpha diversity data would be to
export that data from an available artifact which contains
SampleData[AlphaDiversity], look at that data directly, and then experiment with re-importing it.
Download an alpha diversity result from the Moving Pictures tutorial - for example,
qiime tools export \
--input-path shannon_vector.qza \
Open the resulting
.tsv with your preferred tool (vim, nano, excel, sheets, etc.) to inspect its contents.
qiime tools import on the
.tsv using the type you specified above.