Don't forget mapping files

As suggested in the generic pipeline using Diamond and Megan,

I used ./diamond blastx --query 00fastq/output.fq --db nr --daa 10daa/reads.daa
The reads are paired end merged in a single file called output.fq

I got the result as reads.daa, I meganized this .daa file using MEGAN community version 6
However, I never used any mapping file, I am sorry for this question but I do not really understand the usage

I just went through tabs and clicked on parse seq ids and used files mentioned in the window on Megan

It is not showing any output and I do not know how the output looks like

Please help and correct me where I am going wrong

You need to provide accession mapping files, otherwise meganizing won’t work because the the classification of the reference sequences won’t be known