Just google "Making Bokashi Bran". Lots of information and instructions available. Most call for using EM1 which you can make or purchase. You can use some bokashi bran to breed your own microorganisms and then use that to inoculate more bran. That process would be similar to making JMO except you would use Bokashi instead of leaf mold as the microorganism source.
It's not hard to grow microorganisms. You should look into KNF and JADAM.
There are so many sources of good information online that I'm not going to post any directions. Spend an hour searching online and you'll learn all you need to.