LT8711

Hi I am confused with the explanation regarding some of the calculations for the Boost topology on page 15 of the data sheet for the LT8711.
Please walk me through the step  2 and  3 .  Also  please define for me the units of DC max  and how it relates to the graph on page 5 with the following example...

Min Input voltage 23.8V

Max Input voltage 24.2V

Vout  29 to  30 volts

Output current 3 Amps

Regards
Dave