Firstly, I don't think the link works, well for me I get a 404 error, so a fix for that asap would be grand, as for starting in the music industry for video games / freelance, I'm in the same boat, however I can share what I've learned from people here and from other sources.
Basically, the best thing for a person wanting to get noticed in the music industry is to have a good, polished portfolio. Be it Soundcloud, Youtube or better yet, your own website, it gives people a good insight on pretty much everything they need to know, of course having a certificates is good too, this won't show people what you're capable of, so a good portfolio is a must. Show your best, polished work with various styles and themes would work well for working in the music for media industry.
Advertise, post, network, be part of communities, but most importantly, don't spam. Joining, then spamming on forums with posts like 'check out my music' then just leaving it there and checking back on your post every hour or so to see if you have any replies isn't too good as people will just see that you've registered, posted and then watched (I'll admit, I'm guilty of this in the past, foolish me), give and take feedback. Now this may not be true in some places but for the most part it is. It's always better to get to know a bit about the community, give feedback on others' projects and find out what's going on, this way you will learn tips and tricks a lot better.
As you said 'working for free' is a big thing too, as this will attract much more attention, I mean who are game developers gonna target first? If I were to put myself in their shoes then I'd look for people willing to work for free first rather than jumping straight into paying work. Not only this, but working for free gives you great experience whilst working to deadlines and themes etc. for other people, with the added bonus of having more portfolio work, which then comes back to the first point, so this cycle works greatly in your favour.
I hope this helps, as I'm going by what I've heard from other people and actually doing this right now.