q2-woltka metadata and sample ID

Dear fellowa
I am trying to understand how to add a valid metadata to .sam files.
Apparently, it is required that
" * The input alignment must be multiplexed, with sample ID and an underscore (_) prefixing every read ID."
However, It is clear that I can concatenate fasta, bit is not clear how to add sampleID_ to read ID sam files.
I was rtying to add --rg-id ID_ to bowtie to and it does not work
Even I can read .sam files and do .table.qza with woltka, this is useless without metadata files that i can use with them.

Thank you in advance for you help.
Julian Rozenberg, PhD.