Answer depends on your CrossFit experience.
If you have limited exp, then you should focus on getting the cert. Those seminars will give you the basic foundation of CF. You can't run a successful affiliate without it.
Having exp crossfitting on your own is VERY different than doing it at a CF trained facility.
Again, if you've been on your own, it would be in your best interest to check out affiliates...they can ensure that you are doing the exercises correctly, they might have better/more equip/tools. They show you how to properly coach others and they are a wealth of info. So, find an affiliate and get involved with them.
Okay, if you've been to affiliates and you have ext exp in CF and maybe you're a cert trainer...then affiliate now and start training others (you have a year to get CF cert). To have an affiliate requires insurance which usually requires some cert.
Hope this helps...there is more to it, but this is the gist of it.