AMT Form 6251 Part III was not filled, though this part should be used to calculate the AMT amount according to the statement on Line 7. Could you please direct?

I have a question about the AMT Form 6251. AMT amount is calculated in Line 7, and the line states that "If you reported capital gain distributions directly on Form 1040 or 1040-SR, line 7; you reported qualified dividends on Form 1040 or 1040-SR, line 3a; or you had a gain on both lines 15 and 16 of Schedule D (Form 1040) (as refigured for the AMT, if necessary), complete Part III and enter the amount from line 40 here." I have gain on both lines 15 and 16 of Schedule D (Form 1040). However, the Turbo Tax Premier software does not fill Part III of Form 6251. The AMT section of the software is very brief and only asked a couple of questions, none of which was related to the Part III of Form 6251. Does anyone know how to make the software fill Part III?

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