Building fdroiddata

I ran the command:
git clone F-Droid / Data · GitLab
And after I ran:
fdroid init
And after I put my apk inside the “repo” path and I ran the command:
fdroid update -c
fdroid update
but I received the error:
Ignoring package without metadata: ruttm.apk

I my case I want generate the fdroid customer with my apps, so I am using the pattern whitelabel builds