Hello,
What league(s) are you trying to add?
There are many examples online to get you started. For club leagues,
for example, see the /br-brazil repo [1].
You will need a leagues.txt, a teams.txt and than a folder for the
season w/ (at least) two files, one for the seasons teams e.g.
2015/cb.yml and one for the match schedule (fixtures) e.g.
2015/cb.txt. That's it.
I'd recommend starting w/ your repo, post a link and than we can see
what's not working (or missing) if you try to import the datasets into
an database.
Cheers.
[1]
github.com/openfootball/br-brazil