Co-pilot helped me find the answer! First, you find your AGI which should be listed on your Turbo Tax tax return home page. Then you add any numbers in 1040 line 2a and Schedule 1 line 20 (aside from that, it's just if you have student debt interest or foreign income interest ...which I had neither of ...but if you do, I found Co-pilot to be helpful if you need to find those lines on the return:-)
What do you need the MAGI for? There are several different ways to calculate it for different things.
MAGI is not just one number. It's calculated differently for different purposes. There are about a dozen different definitions of MAGI, depending on what it's being used for. What you found with Copilot is just one of the dozen or so different ways of calculating MAGI. It might not apply to what you are using it for.
What do you need your MAGI for?
Also note that Copilot, like all AI systems, sometimes gives wrong information. You have no way of knowing whether it's right or wrong unless you check it against a reliable source, such as IRS instructions.