Homemade EM = BIM + LB-serum.
I'm sure you can find some healthy woody type places with good soil and natural mulch on top for making BIM.
Second source you need is compost for another batch of BIM.
Now you only need LB-serum and then you can make your own very efficient EM mixing both BIM's and LB together.
Videos from Bryan are good, a bit long, so you can read short versions from one of his teacher here:
http://gilcarandang.com/recipes/
LB (lactobacilli) is first, BIM is the third one.