Issues coming up with lessons for a special needs school.

This is my first semester at interac. I have a driving gig in a small city where I'm assigned to a bunch of high schools and a few special needs schools. I've had a good experience so far, but one of my special needs schools is difficult to plan for.

I go there about one every two weeks. The teachers are nice and supportive, but the big issue is it's difficult to make lesson plans for infrequent classes that vary so much in size and length. I'm 3 months into the school year and I'm meeting classes for the first or second time still.

Interac has SN lesson plans on the company shared drive, but they are complete, 50 min sequential lessons that require too much coordination and physical materials, and I can't figure out any good ways to adapt them for shorter classes. I've been getting better at improvising things for high school classes, but I'm not getting the same amount of teaching experience for special needs. Are there any good resources I can use?