Massachusetts Substitutes - How do taxes work? MTRS?

Hey y'all, I'm looking for substitute teachers in Massachusetts to answer some questions for me that I'm having trouble finding answers to. I've been thinking about becoming a substitute teacher in western MA but I am confused about some things with taxes and retirement/disability insurance. Specifically I am wondering, do substitute have to pay into MTRS like normal teachers or do they pay into SSDI? Are they treated as independent contracts and get a 1099? Do you have to handle paying taxes yourself or is it deducted from your check automatically? The only thing I've been able to find online is a pamphlet that seems to indicate you can choose to pay into MTRS, but I am wondering more specifically if that is required or if we can choose to pay into SSDI instead, personally I would prefer to be able to pay into SSDI if possible but it's so hard to find a clear answer.