Who knows how to set up a bass swarm? (DBA)

I recently upgraded from Martin Logan ESL-X to ESL 13a. I had a pair of REL t7i to go with my esl-x. The new speakers have dual 10 inch Powered subs in each speaker. 
I feel like I could now use my REL subs as part of a DBA now, but I don’t really know how that works. For example, where would I place the subs? What level do I put them, where do I crossover, what’s the air speed of an unladen swallow? 

Who can help?