Play 1-1 until one player scores. Coach rolls the ball up the court. The players play 1-1 according to a 2 digit number called out by the coach. First digit represents a player from Team A and the second digit represents a player from Team B.
Example: Coach calls out "23": The first digit is "2" and the second digit is 3. That mean that Player 2 from Team A plays against Player 3 from Team B.

Whoever gets to the ball first becomes offense.

There is no out of bounds. Fouls are called by the coach.

Improve reaction.
Improve quick first step.
Play hard to the basket.

Also possible as 2-2 or 3-3.
Example: "23" and "54": Players 2 and 5 from Team A against Players 3 and 4 from Team B.

Attack the opposite basket.

Start from baseline or sideline

Foul should only be called on hard fouls.

On 2-2 and 3-3: First number sprints for ball and the rest fights for position.