EE is a 6-month protocol with activities that change every two weeks. Parents/teachers select several multi-sensory activities from a list of 34 activities and do them for the two week period. They work with the child twice a day for about 15-20 minutes each. As the sessions progress, the child gains awareness of sensation and gains multi-sensory integration skills. The activities also build joint-attention skills, which are known to decrease autism severity.
The protocol is simply described in two published papers (listed below). They are open-access (available for free online). In addition, my Hands-On Activities book devotes 80 pages to the protocol, providing perhaps 200 activity variations and talking through program implementation details.
Give it a try and let me know how it goes!
Woo, C. C., & Leon, M. (2013). Environmental enrichment as an effective treatment for autism: A randomized controlled trial. Behavioral Neuroscience, 487-97.
Woo, C., Donnelly, J. H., Steinberg-Epstein, R. R., & Leon, M. (2015). Environmental enrichment as a therapy for autism: a clinical trial replication and extension. Behavioral Neuroscience, 412-422.