Here is a breakdown of how the NBA Draft Lottery works
The NBA Draft Lottery is a weighted system that determines the order that non-playoff teams (or playoff teams that have acquired a lottery pick from a non-playoff team via prior trade) will select in the draft.
There are 1,000 four-number combinations divvied out to each of the 14 draft lottery teams.
The worse record a team had this past season the more four-number combinations they are given. So, the Boston Celtics, who will have the Brooklyn Nets’ pick this year as part of a prior trade, are allotted the most four-number combinations (250 out of 1,000).