The first twenty-four teach the language. These twelve teach the Aṣṭādhyāyī itself — how it is built, how it argues with itself, and how to read a sūtra you have never seen before.
They lean on things this corpus has and few others do: a hand-annotated inheritance graph of 9,266 edges over 3,489 sūtras, 73 governing domains nested nine deep, 133 paribhāṣās, 921 vārttikas, and Patañjali on 1,702 sūtras.
Start with the twenty-four if you have not.